A centrifugal pump volute flow passage parameter optimization method and system

Abstract

The application discloses a centrifugal pump volute flow channel parameter optimization method and system, and relates to the technical field of industrial equipment digital optimization; the method comprises the following steps: based on volute structure data and mechanical seal installation data, the inner wall of the volute is partitioned and identified to obtain a sealing front area, a pressure transmission area and a flow discharge area; based on the sealing front area, the pressure transmission area, the flow discharge area, mechanical seal contact requirement data and target working condition data, contact control analysis is carried out to obtain contact control data; based on the sealing front area, the pressure transmission area, the flow discharge area, the contact control data and the volute structure data, flow channel adjustment item extraction is carried out to obtain regional adjustment data; based on the regional adjustment data, impeller outlet structure data, the contact control data and the target working condition data, flow channel sequence correction is carried out to obtain target flow channel parameters; the application can take into account the sealing working state and the target working condition requirement, and improve the pertinence and adaptability of centrifugal pump volute flow channel parameter optimization.

Description

Technical Field

[0001] This application relates to the field of digital optimization technology for industrial equipment, and more specifically, to a method and system for optimizing the flow channel parameters of a centrifugal pump volute. Background Technology

[0002] With the increasing application of centrifugal pumps in chemical transportation, water supply and drainage, energy equipment, and high-requirement sealing applications, the design of volute flow channel parameters has received widespread attention in centrifugal pump development. To improve the flow state of the fluid at the impeller outlet within the volute, existing technologies typically employ volute geometry design, local backflow structure optimization, high back pressure structure reinforcement, or mechanical seal end-face pressure regulation to handle compression fluctuations at a threshold value, thereby enhancing the centrifugal pump's hydraulic performance, operational stability, or sealing reliability.

[0003] For example, patent application CN103994102A discloses a design method for a spiral compression chamber in a low specific speed centrifugal pump. It designs the compression chamber by providing design formulas for key geometric parameters such as the base circle diameter, tongue inclination angle, diffuser inlet and outlet diameters, and flow cross-sectional dimensions. This type of solution can improve the internal flow of the centrifugal pump to some extent, reduce hydraulic losses, and enhance hydraulic performance and operational stability. However, it primarily focuses on the geometric parameters of the compression chamber itself. When the volute flow channel parameters and the sealing operation state need to be considered simultaneously, the existing technology still does not adequately identify and differentiate the differences in the effects at different locations on the inner wall of the volute.

[0004] For example, the invention patent with publication number CN106351881B discloses an external mixing self-priming centrifugal pump. By setting reflux holes on both sides of the impeller's cross-section symmetrically, it improves the flow state within the volute, thereby reducing hydraulic losses, pressure pulsation, and impeller axial force. This type of solution can improve the flow uniformity within the volute to some extent using a local reflux structure, but it focuses more on improving local flow under a specific reflux structure. When different locations within the volute simultaneously affect the local pressure state, the flow state along the wall, and the outlet discharge state, relying solely on adjustments to the local reflux structure is still insufficient to address the differences in influence between these locations.

[0005] For example, patent application CN104295507A discloses a horizontal high back pressure centrifugal pump unit. It addresses the axial thrust and shaft seal load issues under high back pressure environments through a double-layer volute structure, valve-controlled discharge structure, anti-spiral pressure relief structure, and a combination of mechanical and packing seals. This demonstrates that existing technology recognizes the correlation between pump body flow channel structure, axial thrust, and mechanical seal load. Such solutions can improve operational reliability under specific high back pressure conditions, but they focus more on specific structural reinforcement and pressure relief balance in high back pressure environments. For the design of volute flow channel parameters for general centrifugal pumps under different operating conditions and sealing requirements, existing technology still struggles to balance the influence of flow channel structure with the requirements of sealing operation.

[0006] In addition, another approach in the prior art involves adjusting the end-face pressure from within the mechanical seal itself. For example, patent application CN1594892A discloses a double-end-face mechanical seal for centrifugal pumps, which can automatically adjust the sealing end-face pressure according to the pressure inside the pump chamber to improve sealing reliability, reduce wear, and extend service life. While this approach can improve the working condition of the mechanical seal itself to some extent, the adjustment of the mechanical seal end-face pressure primarily reflects the stress control state of the sealing component itself, while the volute flow channel parameters reflect the flow and pressure transmission state of the fluid within the volute. The two focus on different aspects. The correspondence and constraints between these two influences in the prior art remain unclear, thus easily leading to a difficulty in directly correlating the flow channel design results with the seal's working state.

[0007] Furthermore, under conditions of stringent sealing requirements or significant changes in operating conditions, the impact of different locations on local pressure variations, wall-following flow impact, and outlet discharge status on the inner wall of the volute is usually inconsistent. Some sections of the inner wall near the seal installation location may more easily affect the local stress state of the adjacent area; some sections of the middle inner wall may more easily affect the pressure transmission process and wall-following flow state of the fluid within the volute; and some sections of the inner wall near the outlet may more easily affect fluid discharge and local backflow stagnation. If an integral, empirical, or single-target-oriented flow channel adjustment method is still used, it is easy to encounter situations where the local pressure state at some locations is insufficiently controlled, while wall-following impact or outlet discharge state at other locations is difficult to simultaneously address. Based on the aforementioned existing technologies, it can be seen that although existing solutions address geometric design, local backflow, high back pressure enhancement, and seal face pressure regulation, they still lack a comprehensive understanding of the differences in the impact of different locations on the inner wall of the volute.

[0008] Therefore, the main problem with existing technologies is that when the flow channel parameters of a centrifugal pump volute need to simultaneously consider both the sealing operation state and the target operating conditions, existing optimization methods struggle to simultaneously account for the differences in influence from different locations on the inner wall of the volute, the stability of the sealing operation state, and the adaptability of the flow channel parameters to the target operating conditions. Based on this, how to provide an optimization method that can balance the sealing operation state and the target operating conditions in the design process of centrifugal pump volute flow channel parameters has become a technical problem that needs to be solved in this field. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies where the flow channel parameters of a centrifugal pump volute need to simultaneously consider the differences in influence from different positions on the inner wall of the volute, the stability of the sealing operation, and the adaptability of the flow channel parameters to the target operating conditions when both the sealing working state and target operating conditions are required, this application provides the following technical solution: a method for optimizing the flow channel parameters of a centrifugal pump volute, comprising:

[0010] Collect data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions.

[0011] Based on the volute structure data and mechanical seal installation data, the inner wall of the volute is divided into zones to obtain the pre-sealing zone, pressure transmission zone and unloading zone.

[0012] Based on the contact requirement data of the pre-sealing zone, pressure transmission zone, unloading zone, and mechanical seal, as well as the target operating condition data, contact control analysis is performed to obtain contact control data.

[0013] Based on the pre-sealing zone, pressure transmission zone, unloading zone, contact control data, and volute structure data, flow channel adjustment items are extracted to obtain regional adjustment data;

[0014] Based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data, the flow channel sequence is corrected to obtain the target flow channel parameters.

[0015] Furthermore, methods for obtaining the pre-sealing zone, pressure transmission zone, and unloading zone include:

[0016] Extract the inner wall contour data and the outlet position data of the volute from the volute structure data, and extract the inner wall contour of the volute from the inner wall contour data.

[0017] Extract the mechanical seal retaining ring position data from the mechanical seal installation data;

[0018] Based on the position data of the mechanical seal retaining ring, the inner wall segment of the volute with the smallest distance from the mechanical seal retaining ring is determined in the inner wall profile of the volute, thus obtaining the starting region;

[0019] Based on the volute outlet location data, the volute inner wall segment directly connected to the volute outlet is determined in the volute inner wall contour to obtain the end region.

[0020] Along the extension direction of the inner wall contour of the volute from the starting region to the ending region, the inner wall of the volute between the starting region and the ending region is divided into continuous regions to obtain the intermediate continuous region.

[0021] The initial region is defined as the pre-sealing region, the intermediate continuous region is defined as the pressure transmission region, and the final region is defined as the unloading region.

[0022] Furthermore, methods for obtaining contact control data include:

[0023] Based on the pre-sealing zone, mechanical seal contact requirement data, and target operating condition data, differential pressure control data is obtained;

[0024] Based on the pressure transmission zone, mechanical seal contact requirement data, and target operating condition data, scour control data is obtained;

[0025] Based on the data on the unloading zone, mechanical seal contact requirements, and target operating conditions, exhaust control data is obtained;

[0026] Based on the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the differential pressure control data, scouring control data, and discharge control data are integrated with regional constraints to obtain contact control data.

[0027] Furthermore, methods for obtaining differential pressure control data include:

[0028] Extract the mechanical seal compression range and total clamping force range from the mechanical seal contact requirement data;

[0029] Based on the mechanical seal compression range and the impeller outlet position and direction data in the impeller outlet structure data, determine the pressure change direction in the pre-sealing zone from the impeller outlet to the pressure transmission zone.

[0030] Based on the total clamping force range and the target head in the target working condition data, determine the allowable pressure variation range of the pre-sealing area;

[0031] Based on the distribution of the turning points of the inner wall of the volute in the pre-sealing area in the volute structure data, the pressure change prohibition zone in the pre-sealing area is determined.

[0032] By correlating the pressure change direction, the allowable pressure change range, and the prohibited pressure change range within the same region, differential pressure control data is obtained.

[0033] Furthermore, methods for obtaining scour control data include:

[0034] Extract the end face specific pressure range from the mechanical seal contact requirement data;

[0035] Based on the specific pressure range at the end face, determine the upper limit of the wall-attached flow velocity in the pressure transmission zone;

[0036] Based on the target flow rate in the target operating condition data and the extension direction of the inner wall of the volute located in the pressure transmission zone in the volute structure data, the impact avoidance direction of the pressure transmission zone is determined.

[0037] Based on the arrangement order of the volute inner wall cross sections in the pressure transmission zone in the volute structure data, the progressive continuity order of the pressure transmission zone is determined.

[0038] The flow velocity upper limit, impact avoidance direction, and gradual change sequence are checked to obtain scour control data.

[0039] Furthermore, methods for obtaining emission control data include:

[0040] Extract the total clamping force range and end face specific pressure range from the mechanical seal contact requirement data;

[0041] Based on the total clamping force range and the end face specific pressure range, determine the backflow retention and avoidance zone of the unloading area;

[0042] Based on the target flow rate in the target operating condition data and the volute outlet position data in the volute structure data, determine the end discharge direction of the unloading zone;

[0043] Based on the extension sequence of the end profile of the inner wall of the volute located in the unloading zone in the volute structure data, the opening and closing continuity sequence of the unloading zone is determined.

[0044] The backflow retention and avoidance interval, the end outlet direction, and the opening and dispersing sequence are checked to obtain the discharge control data.

[0045] Furthermore, methods for obtaining regional adjustment data include:

[0046] Pre-sealing adjustment data is obtained based on pre-sealing zone, differential pressure control data, and volute structure data;

[0047] Based on the pressure transmission zone, scour control data, and volute structure data, pressure transmission adjustment data is obtained;

[0048] Based on the unloading zone, exhaust control data, and volute structure data, unloading adjustment data is obtained;

[0049] According to the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data are partitioned and connected to obtain regional adjustment data.

[0050] Furthermore, methods for obtaining pre-closure adjustment data include:

[0051] Based on the pressure change direction, allowable pressure change range, and prohibited pressure change range in the differential pressure control data, multiple volute transition sections in the pre-sealing area were screened:

[0052] Identify the volute transition section located outside the pressure change forbidden zone and whose arrangement direction is consistent with the pressure change direction, and obtain the target volute transition section.

[0053] Extract the transition width and turning point corresponding to the transition part of the target volute;

[0054] Based on the allowable pressure variation range, the transition width and turning point are constrained and matched to obtain pre-sealing adjustment data.

[0055] Furthermore, methods for obtaining pressure adjustment data include:

[0056] Based on the upper limit of the wall-attached flow velocity, the impact avoidance direction, and the sequential change in the scour control data, multiple volute cross-sectional change points in the pressure transmission zone are screened:

[0057] Identify the volute cross-section gradient locations that conform to the impact avoidance direction and satisfy the continuous gradient sequence, and obtain the target volute cross-section gradient locations.

[0058] Extract the cross-sectional gradient direction and gradient rhythm corresponding to the gradient parts of the target volute cross-section;

[0059] Based on the continuous sequence of changes, the direction and rhythm of cross-sectional changes are continuously matched to obtain pressure transmission adjustment data.

[0060] Furthermore, methods for obtaining offflow adjustment data include:

[0061] Based on the backflow retention avoidance zone, end outlet direction, and opening / dispersion continuity sequence in the discharge control data, multiple volute outlet locations in the unloading zone are screened:

[0062] The target volute exit point is obtained by identifying the volute exit point that is located outside the backflow retention avoidance zone and conforms to the end exit direction and opening and closing continuous sequence.

[0063] Extract the outlet direction and end divergence position corresponding to the outlet part of the target volute;

[0064] Based on the continuous sequence of opening and dispersing, the outlet discharge direction and the terminal opening and dispersing position are matched to obtain the unloading adjustment data.

[0065] Furthermore, methods for obtaining target flow channel parameters include:

[0066] Based on regional adjustment data and contact control data, the flow channel sequence is corrected to obtain a set of candidate flow channel parameters.

[0067] Based on the impeller outlet structure data and volute structure data, the candidate flow channel parameter set is filtered for transition continuity to obtain the first candidate flow channel parameter set;

[0068] Based on the contact control data, the first candidate flow channel parameter set is screened by contact control to obtain the second candidate flow channel parameter set;

[0069] Based on the target operating condition data, the second candidate flow channel parameter set is screened for operating condition adaptation to obtain the third candidate flow channel parameter set;

[0070] The candidate flow channel parameters in the third set of candidate flow channel parameters are determined as the target flow channel parameters.

[0071] Furthermore, methods for obtaining the candidate flow channel parameter set include:

[0072] Extract pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data from the regional adjustment data;

[0073] Extract differential pressure control data, flushing control data, and venting control data from the contact control data;

[0074] Based on the differential pressure control data, the transition width and turning point in the pre-sealing adjustment data are corrected to obtain the pre-sealing correction data;

[0075] Based on the scouring control data, the cross-sectional change direction and change rhythm in the pressure transmission adjustment data are corrected to obtain pressure transmission correction data;

[0076] Based on the discharge control data, the outlet discharge direction and the end opening position in the discharge adjustment data are corrected to obtain the discharge correction data;

[0077] Following the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing correction data, pressure transmission correction data, and unloading correction data are connected and arranged in the flow channel segment to obtain a set of candidate flow channel parameters.

[0078] A centrifugal pump volute flow channel parameter optimization system includes:

[0079] The data acquisition module is used to collect data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions.

[0080] The inner wall partition identification module identifies the partitions of the inner wall of the volute based on the volute structure data and mechanical seal installation data, thus obtaining the pre-sealing zone, pressure transmission zone and unloading zone.

[0081] The contact control analysis module performs contact control analysis based on the contact requirement data of the pre-sealing zone, pressure transmission zone, unloading zone, and mechanical seal, as well as the target operating condition data, to obtain contact control data.

[0082] The flow channel adjustment item extraction module extracts flow channel adjustment items based on pre-sealing zone, pressure transmission zone, unloading zone, contact control data and volute structure data to obtain regional adjustment data;

[0083] The flow channel sequence correction module corrects the flow channel sequence based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data to obtain target flow channel parameters.

[0084] Compared with the prior art, the technical effects and advantages of the centrifugal pump volute flow channel parameter optimization method and system of this application are as follows:

[0085] This application does not merely involve conventional adjustments to the overall geometric parameters of the volute flow channel. Instead, it addresses the core contradiction in volute flow channel parameter design—the difficulty in simultaneously balancing the requirements of the sealing working state and the target operating conditions. It constructs a continuous processing chain consisting of data acquisition, inner wall partition identification, contact control analysis, flow channel adjustment item extraction, and flow channel sequence correction. This allows the differences in the effects of different locations on the inner wall of the volute to be transformed into structured processing results that can be reused in subsequent steps. This reduces processing deviations caused by unclear correspondence between flow channel design and sealing working state, difficulty in distinguishing the influence of different locations, and insufficient basis for adapting to target operating conditions in existing technologies. Ultimately, this improves the targeting, consistency, and adaptability of centrifugal pump volute flow channel parameter optimization.

[0086] Firstly, by collecting data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions, and by uniformly recording and organizing the above data, the previously scattered flow channel structure information, seal installation information, seal contact constraint information, and operating condition information can be organized into a unified input result that can be further processed. This reduces the subsequent judgment deviations caused by the scattered design basis and unclear object relationships in the existing technology, and improves the input consistency and result attribution accuracy of the subsequent flow channel parameter optimization process.

[0087] Secondly, by partitioning the inner wall of the volute based on volute structure data and mechanical seal installation data, the pre-sealing zone, pressure transmission zone, and discharge zone are obtained. This allows the inner wall of the volute, which was originally treated as a unified flow channel in the prior art, to be divided into functional parts that have different effects on the local stress near the seal, the fluid pressure transmission process, and the outlet discharge state. This clearly identifies the differences in the influence of different locations on the inner wall of the volute, providing a clear regional basis for subsequent contact control analysis and flow channel adjustment item extraction, and reducing the processing distortion caused by the confusion of functional locations in the prior art.

[0088] Third, by conducting contact control analysis based on the pre-sealing zone, pressure transmission zone, unloading zone, mechanical seal contact requirement data, and target operating condition data, differential pressure control data, flushing control data, and exhaust control data are obtained respectively. This transforms geometric area information, seal contact constraint information, and operating condition constraint information, which were originally difficult to use directly, into structured control results that can be directly called upon in subsequent steps. This improves the correspondence between the volute flow channel parameter design results and the seal working state, and provides a clear basis for the extraction of subsequent area adjustment items, reducing the problem of insufficient constraint basis caused by relying on a single empirical parameter for flow channel adjustment in the existing technology.

[0089] Fourth, by extracting flow channel adjustment items based on contact control data and volute structure data, and correcting the flow channel sequence based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data, the local adjustment results corresponding to the pre-sealing zone, pressure transmission zone, and unloading zone can be organized into a continuously transferable optimization chain. This allows the regional adjustment results obtained in the previous step to serve as the input basis for the subsequent correction and screening, thereby reducing the problems of fragmented local adjustments, unclear connection between front and rear positions, and difficulty in continuously forming optimization results in the existing technology, and improving the coherence and reliability of the target flow channel parameter generation process.

[0090] Therefore, this application not only improves the existing technology in terms of local processing defects such as difficulty in distinguishing the influence of different positions in the design of centrifugal pump volute flow channel parameters, unclear correspondence between flow channel design results and sealing working state, and insufficient basis for target working condition adaptation, but also makes the centrifugal pump volute flow channel parameter optimization process more continuous, targeted and stable, which is more conducive to forming reliable target flow channel parameters in application scenarios that need to take into account both sealing working state and target working condition requirements. Attached Figure Description

[0091] Figure 1 This is a flowchart of a centrifugal pump volute flow channel parameter optimization method according to an embodiment of this application;

[0092] Figure 2 This is a schematic diagram of a centrifugal pump volute flow channel parameter optimization system according to an embodiment of this application;

[0093] Figure 3 This is a schematic diagram of the partition identification and region control relationship of the inner wall of the volute according to an embodiment of this application. Detailed Implementation

[0094] The technical solutions of this application will be described in detail, clearly, and completely below with reference to the accompanying drawings of the embodiments. It should be particularly noted that the specific embodiments described below are only used to better illustrate and explain the technical solutions of this application, and are intended to enable those skilled in the art to better understand and implement this application, and should not be construed as limiting the scope of protection of this application. Without departing from the spirit and substance of this application, those skilled in the art can modify, adjust, or make equivalent substitutions based on the content disclosed in this application, and these modifications, adjustments, or equivalent substitutions should all be considered within the scope of protection of this application.

[0095] Example 1:

[0096] Please see Figure 1 As shown, this embodiment provides a method for optimizing the flow channel parameters of a centrifugal pump volute, including:

[0097] Step S1: Collect volute structure data, impeller outlet structure data, mechanical seal installation data, mechanical seal contact requirement data, and target operating condition data.

[0098] S11. Obtain the three-dimensional structural model of the volute, extract the inner wall boundary, continuously sort the contours, and identify the outlet section on the inner surface of the volute flow channel to obtain the inner wall contour data and the outlet position data of the volute.

[0099] Specifically, the 3D design file of the volute corresponding to the centrifugal pump model to be optimized is read from the built-in design database of the centrifugal pump product, and the 3D design file is converted into a 3D structural model of the volute in a unified coordinate format. The inner surface of the volute flow channel in the 3D structural model is read, and the opening boundary directly connected to the inner hole of the outlet flange is identified. The section where the opening boundary is located is determined as the outlet section of the volute. The geometric center point of the outlet section of the volute is calculated, and the coordinates of the geometric center point are recorded as the outlet position data of the volute. At the same time, the normal direction of the outlet section of the volute is also recorded. After determining the outlet section of the volute, the inner wall contour is sorted. This ensures that the subsequent contour sorting always revolves around the same outlet reference point, avoiding different sorting endpoints selected by different technicians.

[0100] An intermediate reference surface is constructed between the inner surface and outer wall of the volute flow channel along the main extension direction of the flow channel. This intermediate reference surface is taken as the median position of the normal distance between the inner and outer walls of the volute flow channel, and is used to avoid the mounting cavity wall, flange connection surface, and external non-flow channel surfaces. The inner boundary between the inner surface of the volute flow channel and the intermediate reference surface is extracted as a candidate boundary for the inner wall. By using the median position surface, the intermediate reference surface simultaneously avoids local depressions on the inner wall side and mounting structures on the outer wall side, which is beneficial for the stable separation of the volute inner wall boundary that actually participates in fluid transport.

[0101] The candidate boundary of the inner wall is discretely segmented according to the curvature change. In specific implementation, discrete sampling points are set along the extension direction of the candidate boundary of the inner wall, and the local curvature corresponding to each discrete sampling point is calculated; according to the arrangement order of adjacent discrete sampling points, the absolute value of the curvature difference between adjacent discrete sampling points is calculated to obtain the curvature difference sequence.

[0102] The preset curvature difference threshold is determined based on the segmented records of the inner wall boundary in the historical 3D structural model of the volute. Specifically, the historical 3D structural model of the volute that has completed segment verification is read, and the absolute values ​​of the curvature difference between adjacent discrete sampling points marked as smooth transition boundary segments in the inner wall boundary of the historical volute are extracted to form a smooth curvature difference set; the absolute values ​​of the curvature difference between adjacent discrete sampling points marked as geometric transition boundary segments in the inner wall boundary of the historical volute are extracted to form a transition curvature difference set; the overlapping intervals of the smooth curvature difference set and the transition curvature difference set are identified, and the boundary curvature difference that can distinguish between the smooth transition boundary segment and the geometric transition boundary segment is determined as the preset curvature difference threshold. When the number of historical 3D structural models of the volute is insufficient to form a smooth curvature difference set and a transition curvature difference set, the curvature difference sequence of the current candidate inner wall boundary is read, the curvature difference sequence is sorted from smallest to largest, and the boundary position is determined according to the interval distribution between adjacent sorted values ​​in the curvature difference sequence. The curvature difference corresponding to the boundary position is determined as the preset curvature difference threshold.

[0103] When the absolute value of the curvature difference between adjacent discrete sampling points is not greater than a preset curvature difference threshold, the corresponding boundary segments between adjacent discrete sampling points are assigned to the same contour unit. When the absolute value of the curvature difference between adjacent discrete sampling points is greater than the preset curvature difference threshold, segmented boundaries are formed between adjacent discrete sampling points, and the current contour unit ends and the next contour unit begins at the segmented boundary. Through the above processing, the boundary segments corresponding to local smoothing changes are retained in the same contour unit, while the boundary segments corresponding to geometric transition changes are divided into different contour units, resulting in the original inner wall contour composed of multiple adjacent contour units.

[0104] After the original inner wall contour is formed, it is continuously sorted. First, all end contour units are identified; when a contour unit shares a connecting boundary point or connecting boundary line with only one adjacent contour unit, it is determined as an end contour unit. Then, the shortest distance from the geometric center point corresponding to the volute exit position data to the center line of each contour unit is calculated, and the perpendicular point corresponding to the shortest distance is taken as the nearest projection point of the volute exit position data on the original inner wall contour; when the perpendicular point is outside the start and end points of the corresponding contour unit, the endpoint of the contour unit with the smaller distance to the geometric center point corresponding to the volute exit position data is taken as the nearest projection point. Then, taking the midpoint of the center line of each end contour unit as the starting point and the nearest projection point as the ending point, the lengths of the center lines of all adjacent contour units passed sequentially between the starting point and the ending point are counted and accumulated segment by segment to obtain the path distance along the inner wall from each end contour unit to the volute exit position data; the end contour unit with the largest path distance along the inner wall is taken as the sorting starting point. After adopting this sorting rule, the inner wall contour of the volute is arranged sequentially from the end furthest from the volute outlet to the end closest to the volute outlet, forming a unique contour sorting result, so that the global path coordinates can always maintain a unidirectional increasing trend.

[0105] The length of a contour unit is calculated as follows: when the contour unit is a straight line segment, the Euclidean distance between its starting and ending points is taken as the centerline length; when the contour unit is a curved segment, the arc length of its centerline is taken as the centerline length. The method for determining the continuous connection of adjacent contour units is as follows: when the current contour unit and the next contour unit share a connection boundary point or a connection boundary line, they are determined to be continuously connected; when they neither share a connection boundary point nor a connection boundary line, a contour breakpoint is determined, and a verification mark is generated.

[0106] After determining the sorting starting point, the starting point is used as the initial contour unit, and adjacent contour units are sorted sequentially according to their continuous connection relationship to obtain all contour units arranged in front-to-back order. All contour units are recorded as the inner wall contour data of the volute, where each contour unit includes at least the contour unit number, starting point coordinates, ending point coordinates, and local extension direction. Subsequently, the cumulative path length along the inner wall from the sorting starting point to the midpoint of the centerline of each contour unit is calculated, and the cumulative path length along the inner wall is recorded as the global path coordinates of the corresponding contour unit, thus obtaining the inner wall contour data of the volute and the volute exit position data.

[0107] S12, acquire the three-dimensional structural model of the impeller, locate the outlet position and extract the outlet direction of the impeller outlet, and obtain the impeller outlet position data and impeller outlet direction data.

[0108] Specifically, the impeller 3D design file corresponding to the centrifugal pump model to be optimized is read from the design database built into the centrifugal pump product, and the impeller 3D design file is converted into a 3D structural model of the impeller in a unified coordinate format; the impeller outlet geometry in the 3D structural model of the impeller is read, the impeller outlet annular section is extracted, the geometric center point of the impeller outlet annular section is calculated, and the coordinates of the geometric center point are recorded as the impeller outlet position data.

[0109] When extracting the impeller outlet direction, the boundary curves of each blade outlet edge on the impeller outlet annular cross-section are read, and the edge tangential direction is established at the midpoint of each blade outlet edge. Then, in the volute inner wall contour data, the volute inner wall point with the smallest distance to the geometric center point corresponding to the impeller outlet position data is taken as the nearest inner wall point on the volute inlet side, and the direction pointing from the geometric center point corresponding to the impeller outlet position data to the nearest inner wall point on the volute inlet side is taken as the positive reference direction for the outlet. The tangential direction of each blade outlet edge is homogenized: when the angle between the tangential direction of a blade outlet edge and the positive reference direction for the outlet is greater than 90 degrees, the tangential direction is reversed; when the angle is not greater than 90 degrees, the tangential direction remains unchanged. After homogenization, all tangential directions are vector averaged to obtain the impeller outlet average direction vector. Then, each component of this average direction vector is divided by its modulus to obtain the impeller outlet direction data. By unifying the tangential direction of each blade's exit edge by using the positive reference direction at the exit, we can avoid the distortion of the average direction caused by the mixing of positive and negative local tangential directions of different blades.

[0110] After the impeller outlet direction data is generated, its stability is assessed. Specifically, the angular deviation between the tangential direction of each blade outlet edge and the average impeller outlet direction vector is calculated, and then the arithmetic mean of all angular deviations is calculated to obtain the nominal impeller outlet deviation angle. The nominal impeller outlet deviation angle is multiplied by the outlet direction ratio threshold to obtain the direction dispersion judgment value. The outlet direction ratio threshold is obtained by statistically analyzing the angular deviation between the tangential direction of each blade outlet edge and the corresponding average impeller outlet direction vector in historically verified centrifugal pump prototypes, and calculating the ratio between the nominal impeller outlet deviation angle of each prototype and the maximum angular deviation. All ratios are sorted from smallest to largest, and the median value is taken as the outlet direction ratio threshold. When the directional dispersion judgment value is less than the preset dispersion upper limit, the preset dispersion upper limit is taken as the directional dispersion judgment result. The preset dispersion upper limit is obtained by: acquiring historically verified centrifugal pump prototype impeller outlet direction detection records, statistically analyzing the included angle fluctuation values ​​caused by machining errors, assembly errors, and measurement errors under stable impeller outlet direction conditions for each prototype; sorting all included angle fluctuation values ​​from smallest to largest and taking the upper quartile value as the preset dispersion upper limit, to avoid misjudging geometric perturbations as directional instability when directional dispersion is extremely small. When the maximum included angle deviation is not greater than the preset dispersion upper limit, the impeller outlet direction data is determined to be valid; when the maximum included angle deviation is greater than the preset dispersion upper limit, the impeller outlet direction data is determined to be unstable, and a verification mark is generated. This dual-layer judgment ensures that directional stability adaptively adjusts with the current blade outlet dispersion level without losing minimum engineering resolution due to extremely small dispersion, thus obtaining impeller outlet position data and impeller outlet direction data.

[0111] S13, obtain the mechanical seal assembly model, perform center positioning, mounting surface direction identification and outer diameter range reading of the mechanical seal retaining ring installation part, and obtain the mechanical seal retaining ring position data.

[0112] Specifically, the mechanical seal retaining ring mounting location in the mechanical seal assembly model is read, the outer edge boundary of the sealing end face of the mechanical seal retaining ring is extracted, the geometric center point of the area enclosed by this outer edge boundary is calculated, and this geometric center point is determined as the center point coordinate of the sealing end face of the mechanical seal retaining ring. Then, the plane containing the mechanical seal retaining ring mounting surface is extracted, and the unit normal vector of this plane is taken as the normal direction of the mounting surface. Subsequently, within the plane containing the sealing end face of the mechanical seal retaining ring, the distance from each boundary point on the outer edge boundary to the center point coordinates is calculated. Twice the minimum value of all distances is taken as the lower limit of the outer diameter, and twice the maximum value of all distances is taken as the upper limit of the outer diameter, thus obtaining the outer diameter range of the mechanical seal retaining ring. Finally, the center point coordinates, the normal direction of the mounting surface, and the outer diameter range are recorded together as the mechanical seal retaining ring position data.

[0113] After the mechanical seal retaining ring position data is generated, its validity is determined. Specifically, the outer edge position of the mechanical seal mounting cavity is determined based on the mechanical seal retaining ring position data. Then, a projection is made from the outer edge of the mechanical seal mounting cavity towards the volute flow channel in the normal direction of the mounting surface, forming a projection band. The set of contour units obtained by the intersection of the projection band and the volute inner wall contour data is taken as the adjacent inner wall of the volute. If there are no intersecting contour units between the projection band and the volute inner wall contour data, the three consecutive contour units with the smallest normal distance from the outer edge of the mechanical seal mounting cavity are taken as the adjacent inner wall of the volute. The three consecutive contour units can cover the minimum adjacent inner wall length corresponding to the outer diameter range of the mechanical seal retaining ring, and avoid the adjacent range being too narrow when only a single contour unit is taken. Subsequently, the maximum normal distance from the outer edge of the mechanical seal mounting cavity to the adjacent inner wall of the volute is calculated. When the maximum normal distance is not greater than the upper limit of the design envelope distance, the mechanical seal retaining ring position data is determined to be valid. When the maximum normal distance is greater than the upper limit of the design envelope distance, the mechanical seal retaining ring position data is determined to have an assembly correspondence error, and a verification mark is generated. The upper limit of the design envelope distance is preferentially read from the design value in the mechanical seal assembly model. When the mechanical seal assembly model does not directly record this value, the maximum normal distance between the outer edge coordinates of the mechanical seal mounting cavity and the contour coordinates of the adjacent inner wall of the volute is calculated, and the calculation result is used as the upper limit of the design envelope distance. After this processing, even if the design envelope distance is not given separately in the assembly model, a unique validity check boundary can still be formed based on the existing geometric data to obtain the mechanical seal retaining ring position data.

[0114] S14, obtain the mechanical seal technology sample, read and verify the parameters of the mechanical seal compression range, total clamping force range and end face specific pressure range, and obtain the mechanical seal compression range, total clamping force range and end face specific pressure range.

[0115] Specifically, the upper and lower limits of the installation compression amount are read from the mechanical seal technical sample to obtain the mechanical seal compression range; the minimum and maximum allowable total clamping force values ​​are read from the mechanical seal technical sample to obtain the total clamping force range; and the lower and upper limits of the end-face allowable specific pressure are read from the mechanical seal technical sample to obtain the end-face specific pressure range. Then, the ranges of the above three parameters are checked: if the mechanical seal compression range, total clamping force range, and end-face specific pressure range all simultaneously contain clearly defined lower and upper limits, the check is considered passed; if any one of them lacks a clearly defined lower or upper limit value, the check is considered failed, and a missing value marker is generated. Only when both upper and lower limits exist can the subsequent pressure range, backflow avoidance range, and screening threshold stably fall within the clearly defined constraint boundaries. Finally, the mechanical seal compression range, total clamping force range, and end-face specific pressure range are collectively recorded as the mechanical seal contact requirement data.

[0116] S15, obtain the project selection sheet and project technical condition table, determine and verify the working conditions of the flow rate, head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, mechanical seal leakage allowable value and whole machine vibration amplitude allowable value at the target working point, and obtain the target working condition data.

[0117] Specifically, the flow rate and head values ​​corresponding to all operating points in the project selection list are read. When a clearly specified operating point exists in the project selection list, that specified operating point is designated as the target operating point. When no clearly specified operating point exists in the project selection list, but a rated operating point identifier exists, the operating point corresponding to the rated operating point identifier is designated as the target operating point. When neither a clearly specified operating point nor a rated operating point identifier exists in the project selection list, the first operating point in the project selection list arranged in record order is designated as the target operating point. Using this sequential fallback rule ensures that a unique target operating point can still be obtained even when a priority operating point identifier is missing in the project selection list, preventing subsequent operating point adaptation and selection from losing a unified reference.

[0118] After the target operating point is determined, the flow rate and head value corresponding to the target operating point are read and recorded as the target flow rate and target head, respectively; then the conveying medium category field, conveying medium design density field, conveying medium design kinematic viscosity field and solid volume fraction field corresponding to the target operating point are read from the project selection form.

[0119] When the project selection form does not record the design density, design kinematic viscosity, or solid volume fraction of the conveying medium, actual measurements are performed on the target conveying medium sample. Density measurement is performed using a densitometer at a preset reference temperature; kinematic viscosity measurement is performed using a capillary viscometer at the same preset reference temperature; and the solid volume fraction is determined using the gravimetric method or centrifugal sedimentation method. The preset reference temperature is determined based on the temperature recorded for the medium parameters in the project selection form. If the project selection form does not record the temperature for the medium parameters, the reference measurement temperature specified in the medium property testing standard is used as the preset reference temperature. After measuring the design density and design kinematic viscosity of the conveying medium at the same preset reference temperature, different batches of medium records can proceed to the subsequent operating condition judgment process according to the same temperature caliber.

[0120] When the target transport medium category is determined, if the designed kinematic viscosity of the transport medium is not less than the high viscosity determination threshold, the target transport medium is determined as a high viscosity medium; wherein, the high viscosity determination threshold is obtained by obtaining the boundary viscosity value between conventional liquids and high viscosity liquids in the centrifugal pump medium classification table, and determining the boundary viscosity value as the high viscosity determination threshold.

[0121] When the solid volume fraction is not less than the solid content determination threshold, the target transport medium is determined to be a solid content medium; wherein, the solid content determination threshold is obtained by obtaining the minimum solid volume fraction corresponding to when the solid particles in the solid-liquid two-phase transport application boundary begin to have a stable influence on the flow state, and determining the minimum solid volume fraction as the solid content determination threshold.

[0122] When the designed kinematic viscosity of the conveying medium is not less than the high viscosity threshold and the solid volume fraction is not less than the solid content threshold, the target conveying medium is determined to be a high viscosity solid content medium; when the designed kinematic viscosity of the conveying medium is not less than the high viscosity threshold and the solid volume fraction is less than the solid content threshold, the target conveying medium is determined to be a high viscosity medium; when the designed kinematic viscosity of the conveying medium is less than the high viscosity threshold and the solid volume fraction is not less than the solid content threshold, the target conveying medium is determined to be a solid content medium; when the designed kinematic viscosity of the conveying medium is less than the high viscosity threshold and the solid volume fraction is less than the solid content threshold, the target conveying medium is determined to be a conventional medium.

[0123] After classifying the target conveying medium according to its design kinematic viscosity and solid volume fraction, the matching conditions of the subsequent equivalent test medium can be constrained according to the viscosity characteristics and solid content characteristics of the target conveying medium, respectively. This ensures that the upper limit of the wall-attached flow velocity, the backflow retention and avoidance ratio, and the operating condition adaptation boundary formed in the representative centrifugal pump prototype test are consistent with the actual conveying characteristics of the current target conveying medium. The permissible mechanical seal leakage and permissible overall vibration amplitude fields are read from the project technical conditions table. If the permissible mechanical seal leakage or permissible overall vibration amplitude field is not recorded in the project technical conditions table, a missing marker is generated. The read permissible mechanical seal leakage field is recorded as the permissible mechanical seal leakage value, and the read permissible overall vibration amplitude field is recorded as the permissible overall vibration amplitude value.

[0124] A corresponding verification is then performed: if the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, allowable mechanical seal leakage, and allowable overall machine vibration amplitude all originate from the same operating condition record or the same sample measurement record corresponding to the target operating point, and there are no missing markers, the correspondence is deemed valid; otherwise, the correspondence is deemed invalid, and a verification marker is generated. Finally, the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, allowable mechanical seal leakage, and allowable overall machine vibration amplitude are collectively recorded as the target operating condition data.

[0125] S16 performs a unified spatial reference conversion on the volute inner wall contour data, volute outlet position data, impeller outlet position data, impeller outlet direction data, and mechanical seal retaining ring position data. It also performs integrity verification and corresponding recording on the mechanical seal compression range, total clamping force range, end face specific pressure range, and target operating condition data to obtain volute structure data, impeller outlet structure data, mechanical seal installation data, mechanical seal contact requirement data, and target operating condition data.

[0126] Specifically, the impeller rotation axis is used as the reference axis, the projection point of the geometric center point of the impeller outlet annular section onto the reference axis is used as the coordinate origin, and the direction from the coordinate origin to the geometric center point of the volute outlet section is used as the first reference direction. The angle between the first reference direction and the reference axis is calculated, and the projection ratio of the first reference direction in the plane perpendicular to the reference axis is calculated. When the projection ratio is not less than a preset lower limit of the projection ratio, the first reference direction is used as the X-axis direction. The preset lower limit of the projection ratio is preset according to the requirements for the differentiation of direction components when the coordinate axis is established, and the minimum angle threshold is the angle value corresponding to the preset lower limit of the projection ratio.

[0127] When the included angle is less than the minimum included angle threshold, the normal direction of the volute exit section is projected onto a plane perpendicular to the reference axis, and the resulting projection direction is used as the first reference direction; when the projection length of the projection direction is not greater than the preset lower limit, the local extension direction of the contour unit corresponding to the sorting starting point is projected onto a plane perpendicular to the reference axis, and the resulting projection direction is used as the first reference direction; wherein, the preset lower limit is used to exclude the situation of directional instability caused by the projection direction being too short.

[0128] After determining the first reference direction, the reference axis is used as the Z-axis direction, the first reference direction is used as the X-axis direction, and the Y-axis direction is determined according to the right-hand rule. Through the above direction determination method, the unified coordinate system can still maintain a clear planar projection direction when the angle between the volute exit direction and the rotation axis is small, thus ensuring that subsequent position and direction conversions are based on the same spatial reference.

[0129] After the coordinate axes are established, all position and direction quantities in the volute inner wall contour data, volute outlet position data, impeller outlet position data, impeller outlet direction data, and mechanical seal retaining ring position data are projected onto the X-axis, Y-axis, and Z-axis directions respectively to obtain position coordinates and direction components under a unified spatial reference.

[0130] The system verifies the completeness of the following data: volute inner wall contour data, volute outlet position data, impeller outlet position data, impeller outlet direction data, mechanical seal retaining ring position data, mechanical seal compression range, total clamping force range, end face specific pressure range, and target operating condition data. If all of these data are present, and the target operating condition data includes at least the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, mechanical seal leakage allowable value, and overall machine vibration amplitude allowable value, the currently acquired data record is considered complete. If any of these items are missing, the currently acquired data record is considered incomplete, and the name of the missing data item is returned.

[0131] After the integrity check is passed, the volute inner wall contour data and volute outlet position data are jointly recorded as volute structure data; the impeller outlet position data and impeller outlet direction data are jointly recorded as impeller outlet structure data; the mechanical seal retaining ring position data is recorded as mechanical seal installation data; and the mechanical seal compression range, total clamping force range, and end face specific pressure range are jointly recorded as mechanical seal contact requirement data. The target operating condition data is kept as the uniformly recorded target operating condition data. Then, a data record table is created, and the above data are written into the same data record according to the uniform field names and uniform record order. After corresponding recording according to the uniform field names and uniform record order, the volute structure data, impeller outlet structure data, mechanical seal installation data, mechanical seal contact requirement data, and target operating condition data can maintain a one-to-one correspondence within the same record. Subsequent partition identification, contact control analysis, area adjustment item extraction, and flow channel sequence correction are all performed around the same record, avoiding mismatches between geometric information, contact constraints, and operating parameters caused by cross-record calls.

[0132] Step S2: Based on the volute structure data and mechanical seal installation data, the inner wall of the volute is divided into zones to obtain the pre-sealing zone, pressure transmission zone, and unloading zone.

[0133] S21, Read the inner wall contour data and outlet position data of the volute from the volute structure data, read the position data of the mechanical seal fixing ring from the mechanical seal installation data, and restore the inner wall contour of the volute according to the contour unit number to obtain the contour sequence to be partitioned.

[0134] Specifically, the inner wall contour data of the volute is read from the volute structure data; each contour unit in the volute inner wall contour data includes at least a contour unit number, start coordinates, end coordinates, local extension direction, and global path coordinates. The contour units are connected sequentially according to their numbers; when a contour unit is a straight line segment, the line connecting the start and end points of the contour unit is used as the center line; when a contour unit is a curved segment, the central axis curve of the contour unit is used as the center line, resulting in the contour sequence to be partitioned. Subsequently, the volute outlet position data and the mechanical seal retaining ring position data are read.

[0135] After the contour sequence to be partitioned is formed, a pre-partition check is performed. Specifically, first check whether the contour data of the inner wall of the volute is accompanied by a verification mark; if no verification mark is accompanied, it is determined that the contour sequence to be partitioned meets the basic contour conditions; if a verification mark is accompanied, it is determined that the contour sequence to be partitioned does not meet the basic contour conditions, and a partition verification mark is generated.

[0136] Next, check whether the mechanical seal retaining ring position data and the volute outlet position data both exist. If both the mechanical seal retaining ring position data and the volute outlet position data exist, it is determined that the contour sequence to be partitioned meets the basic positioning conditions. If either the mechanical seal retaining ring position data or the volute outlet position data is missing, it is determined that the contour sequence to be partitioned does not meet the basic positioning conditions, and a partition verification mark is generated.

[0137] Next, count the total number of contour units in the contour sequence to be partitioned; when the total number of contour units is not less than the preset minimum number of partitions, it is determined that the contour sequence to be partitioned meets the minimum number of partitions requirement; when the total number of contour units is less than the preset minimum number of partitions, it is determined that the contour sequence to be partitioned does not meet the minimum number of partitions requirement, and a partition verification mark is generated.

[0138] The preset minimum number of partitions is obtained by: determining that each partition corresponds to at least one minimum contour unit according to the partition identification requirements of the pre-sealing area, pressure transmission area and unloading area, and then adding the number of minimum contour units corresponding to each partition to obtain the preset minimum number of partitions.

[0139] If a partition verification mark exists, subsequent partition identification will not proceed.

[0140] S22, Based on the position data of the mechanical seal retaining ring, determine the volute inner wall segment with the smallest distance from the mechanical seal retaining ring in the contour sequence to be partitioned, and obtain the starting region.

[0141] Specifically, the coordinates of the center point of the sealing end face of the mechanical seal retaining ring, the normal direction of the mounting surface, and the outer diameter range of the mechanical seal retaining ring are read from the mechanical seal retaining ring position data. For each contour unit in the contour sequence to be partitioned, the midpoint of its centerline is taken as a representative point; the Euclidean distance from this representative point to the center point of the sealing end face of the mechanical seal retaining ring is calculated to obtain the nearest neighbor distance; then, this representative point is projected onto the plane where the mounting surface is located, and the distance from the projected point to the center point of the sealing end face of the mechanical seal retaining ring within the mounting surface is calculated to obtain the projected nearest neighbor distance.

[0142] The candidate set of the starting region is determined based on the outer diameter range of the mechanical seal retaining ring. Specifically, the lower and upper limits of the outer diameter within the mechanical seal retaining ring's outer diameter range are read, and their arithmetic mean is calculated. Half of this arithmetic mean is then used as the reference influence radius. Using half of the median value of the outer diameter range as the reference influence radius can simultaneously cover normal assembly fluctuations between the upper and lower limits of the outer diameter, avoiding the initial region identification being biased towards only one side of the dimensional boundary. Next, the arithmetic mean of the centerline lengths of all contour units in the contour sequence to be partitioned is calculated and used as the contour discrete compensation length. The contour discrete compensation length is taken as the average segmentation scale in the current discrete representation of the volute inner wall, used to compensate for boundary deviations caused by the discrete segmentation of contour units, ensuring that the starting region does not experience local jumps due to excessively dense or sparse individual contour units. When the projected proximity distance of a contour unit is not greater than the sum of the reference influence radius and the contour discrete compensation length, the contour unit is included in the candidate set of the starting region; otherwise, it is not included. By using half of the median value of the outer diameter range as the reference radius of influence, the candidate set of the starting area can cover the normal assembly corresponding area within the fluctuation range of the outer diameter of the mechanical seal retaining ring, without excessively expanding to the inner wall section of the volute far from the mechanical seal retaining ring, so that the starting position of the pre-sealing area is always formed around the contact sensitive area of ​​the mechanical seal.

[0143] When the candidate set of the starting region is empty, the contour unit with the smallest projected proximity distance is selected as the core contour unit of the starting region, and a partition verification mark is generated. When multiple contour units have the same and the same minimum projected proximity distance, the contour unit with the smallest proximity distance is selected as the core contour unit of the starting region. When both the projected proximity distance and the proximity distance are the same, the contour unit with the smaller contour unit number is selected as the core contour unit of the starting region. The above sorting rules are used to form a unique core contour unit of the starting region among multiple equal candidate contour units.

[0144] When the candidate set of the starting region is not empty, the core contour unit of the starting region is determined in the candidate set of the starting region. Specifically, the contour unit with the smallest neighbor distance is selected as the core contour unit of the starting region. When there are multiple contour units with the same neighbor distance and both are the minimum value, the contour unit with the smallest projected neighbor distance is selected as the core contour unit of the starting region. When both the neighbor distance and the projected neighbor distance are the same, the contour unit with the smaller contour unit number is selected as the core contour unit of the starting region.

[0145] After the core contour unit of the starting region is determined, it is continuously expanded along the direction of decreasing contour unit number and the direction of increasing contour unit number, respectively. When an adjacent contour unit is located in the candidate set of the starting region, and the difference between the adjacent contour unit's proximity distance and the proximity distance of the core contour unit of the starting region is not greater than the contour discrete compensation length, the adjacent contour unit is included in the starting region. When an adjacent contour unit is not located in the candidate set of the starting region, or the difference between its proximity distance and the proximity distance of the core contour unit of the starting region is greater than the contour discrete compensation length, the expansion in that direction is stopped, and the starting region is obtained.

[0146] S23, Based on the volute outlet location data, determine the volute inner wall segment directly connected to the volute outlet in the contour sequence to be partitioned, and obtain the end region.

[0147] Specifically, the geometric center point of the volute exit section and the normal direction of the volute exit section are read from the volute exit position data. For each profile unit in the profile sequence to be partitioned, the Euclidean distance from the start and end points of the profile unit to the geometric center point of the volute exit section is calculated, and the smaller value is taken as the exit proximity distance; then, the absolute values ​​of the normal distances from the start and end points of the profile unit to the plane where the volute exit section is located are calculated, and the smaller value is taken as the exit normal distance.

[0148] Determine the candidate set of the end region. Specifically, first calculate the arithmetic mean of the centerline lengths of all contour units in the contour sequence to be partitioned, and use this as the exit connection compensation length. For each contour unit, determine whether to include it in the candidate set of the end region according to the following rules: When the start or end point of the contour unit shares a connection boundary point or a connection boundary line with the volute exit section boundary, the contour unit is directly included in the candidate set of the end region; when the contour unit is not directly connected to the volute exit section boundary, but its exit normal distance is not greater than the exit connection compensation length, and the exit proximity distance is within the range of the first preset number of different distance values ​​after sorting from smallest to largest, the contour unit is also included in the candidate set of the end region; otherwise, it is not included.

[0149] The preset number of near-end distances is obtained as follows: based on the minimum coverage requirement for the continuous discharge range at the end in the unloading zone identification, it is determined that in addition to the inner wall section directly connected to the volute outlet, the minimum number of continuous inner wall layers directly adjacent to the inner wall section should also be covered, and the number of different distance values ​​corresponding to the minimum number of continuous inner wall layers is determined as the preset number of near-end distances.

[0150] After forming a candidate set of end regions by using a number of different distance values ​​of the pre-set near-end distance, the end regions not only cover the inner wall section directly connected to the volute outlet, but also cover the smallest continuous outgoing range directly adjacent to the inner wall section. This makes the extraction of the outgoing part of the subsequent unloading area not limited to a single end contour unit, and can form a continuous end structure that can be used to determine the outgoing direction and compare the end divergence position.

[0151] When the candidate set for the end region is empty, the contour unit with the smallest exit proximity distance is selected as the core contour unit for the end region, and a partition verification mark is generated. When multiple contour units have the same exit proximity distance and are all at the minimum value, the contour unit with the smallest exit normal distance is selected as the core contour unit for the end region. When both the exit proximity distance and the exit normal distance are the same, the contour unit with the larger contour unit number is selected as the core contour unit for the end region. The above sorting rules are used to form a unique core contour unit for the end region among multiple candidate contour units.

[0152] When the candidate set of the terminal region is not empty, the core contour unit of the terminal region is determined from the candidate set of the terminal region. Specifically, the contour unit with the smallest exit proximity distance is selected as the core contour unit of the terminal region. When multiple contour units have the same exit proximity distance and are both the minimum, the contour unit with the smallest exit normal distance is selected as the core contour unit of the terminal region. When both the exit proximity distance and the exit normal distance are the same, the contour unit with the larger contour unit number is selected as the core contour unit of the terminal region.

[0153] After the core contour unit of the terminal region is determined, it is used as the starting point to locally expand along the direction of decreasing contour unit number and the direction of increasing contour unit number respectively. When an adjacent contour unit is located in the candidate set of the terminal region and the difference between its exit proximity distance and the exit proximity distance of the core contour unit of the terminal region is not greater than the exit connection compensation length, the adjacent contour unit is included in the terminal region; otherwise, the expansion in this direction is stopped, and the terminal region is obtained.

[0154] S24, when neither the initial region identification nor the final region identification generates a partition verification mark, the inner wall of the volute between the initial region and the final region is divided into continuous regions along the extension direction of the inner wall of the volute from the initial region to the final region to obtain the intermediate continuous region.

[0155] Specifically, in the contour sequence to be partitioned, the starting and ending numbers of the starting region and the ending region are determined respectively; wherein, the starting number of the starting region is the minimum value of the contour unit number in the starting region, and the ending number of the starting region is the maximum value; the starting number of the ending region is the minimum value of the contour unit number in the ending region, and the ending number of the ending region is the maximum value.

[0156] When there are contour units to be divided between the end number of the starting region and the start number of the ending region, all continuous contour units whose numbers are after the end number of the starting region and before the start number of the ending region are determined as the intermediate continuous region.

[0157] When there are no contour units to be divided between the end number of the starting region and the starting number of the ending region, the starting region is first adjusted to the smallest starting region containing only the core contour units of the starting region, and then the ending region is adjusted to the smallest ending region containing only the core contour units of the ending region. If there are at least contour units to be divided between the adjusted core contour units of the starting region and the adjusted core contour units of the ending region, then all continuous contour units between them are determined as the intermediate continuous region. If there are still no contour units to be divided after adjustment, a partition verification mark is generated. After adopting the above adjustment method, when the starting region and the ending region are close or partially overlapped, their respective core contour units are still retained first, and it is further determined whether there is a continuous inner wall segment between them that can be used to form the intermediate continuous region, thereby avoiding the direct loss of the pressure transmission zone simply because the region boundaries are close.

[0158] After the intermediate continuous region is formed, a minimum continuity check is performed on the intermediate continuous region. When the total number of contour units in the intermediate continuous region is not less than the preset minimum number of continuous region units, the intermediate continuous region is determined to be valid. When the total number of contour units in the intermediate continuous region is less than the preset minimum number of continuous region units, the intermediate continuous region is determined to be invalid, and a partition check mark is generated.

[0159] The method for obtaining the preset minimum continuous region unit number is as follows: based on the minimum structural requirements of the continuous inner wall segment for pressure transmission zone identification, the minimum contour unit number that can independently form the pressure transmission zone is determined, and this minimum contour unit number is determined as the preset minimum continuous region unit number.

[0160] S25, the starting area is defined as the pre-sealing area, the intermediate continuous area is defined as the pressure transmission area, and the terminal area is defined as the unloading area.

[0161] Specifically, when the intermediate continuous region is valid and no partition verification mark is generated, the boundaries of the starting region, intermediate continuous region, and ending region are first checked. The boundary check is performed as follows: check whether there are duplicate contour units among the starting region, intermediate continuous region, and ending region; if there are no duplicate contour units, the boundaries are determined to be non-overlapping; if there are duplicate contour units, the boundaries are determined to be overlapping, and a partition verification mark is generated. Then, check whether the starting region, intermediate continuous region, and ending region maintain sequential continuity along the contour unit numbering direction; if the maximum contour unit number of the starting region is less than the minimum contour unit number of the intermediate continuous region, and the maximum contour unit number of the intermediate continuous region is less than the minimum contour unit number of the ending region, the order relationship is determined to be valid; otherwise, the order relationship is determined to be invalid, and a partition verification mark is generated.

[0162] When the boundary check passes, the starting area is designated as the pre-sealing area, the intermediate continuous area is designated as the pressure transmission area, and the terminal area is designated as the unloading area. The corresponding set of contour unit numbers, contour unit coordinates, local extension direction, and global path coordinates for each area are written into the partitioning result table, so that subsequent steps can directly call the corresponding geometric information based on the pre-sealing area, pressure transmission area, and unloading area. When the boundary check fails, only the partitioning review mark and the corresponding reason are recorded, and it is not written into the partitioning result.

[0163] Please see Figure 3 As shown, Figure 3 This diagram illustrates the partitioning and regional control relationships of the volute inner wall according to an embodiment of this application. Based on the position of the mechanical seal retaining ring and the volute outlet position, the volute inner wall is divided into a pre-sealing zone, a pressure transmission zone, and a discharge zone. The pre-sealing zone is used for pressure variation control corresponding to the front side of the mechanical seal; the pressure transmission zone is used for impact avoidance control during fluid transmission along the volute inner wall; and the discharge zone is used for end-of-line discharge control and backflow retention avoidance control during fluid discharge. Based on the pre-sealing zone, pressure transmission zone, and discharge zone, further contact control analysis is performed.

[0164] Step S3: Based on the contact requirement data of the pre-sealing zone, pressure transmission zone, flow discharge zone, mechanical seal, and target operating condition data, conduct contact control analysis to obtain contact control data.

[0165] S31, read the corresponding contour units from the pre-sealing zone, pressure transmission zone and unloading zone respectively, read the mechanical seal compression range, total clamping force range and end face specific pressure range from the mechanical seal contact requirement data, and read the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity and solid phase volume fraction from the target working condition data to obtain the contact control analysis input dataset.

[0166] Specifically, the corresponding contour unit numbers, local extension directions, contour unit coordinates, and global path coordinates are read from the pre-sealing zone, pressure transmission zone, and unloading zone, respectively. The mechanical seal compression range, total clamping force range, and end face specific pressure range are read from the mechanical seal contact requirement data. The target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, and solid volume fraction are read from the target operating condition data. Subsequently, the inner wall cross-section of the pressure transmission zone and the end inner wall cross-section of the unloading zone are extracted in the order of the source contour unit numbers. The extraction method of the inner wall cross-section is as follows: take the midpoint of the center line of the contour unit as the cross-section reference point, construct the local cross-section line with the normal direction of the local extension direction at the cross-section reference point, and then take the intersection line segment between the local cross-section line and the local inner wall boundary enclosed by the contour unit and its adjacent contour units as the corresponding inner wall cross-section.

[0167] Verify the completeness of the input dataset for contact control analysis. When the pre-sealing zone, pressure transmission zone, and unloading zone are all non-empty, the mechanical seal compression range, total clamping force range, and end face specific pressure range all contain clear upper and lower limits, and the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, and solid volume fraction all exist, and the inner wall cross-section sequence of the pressure transmission zone and the end inner wall cross-section sequence of the unloading zone have been formed, the input dataset for contact control analysis is deemed valid. If any of these conditions are not met, a contact analysis verification mark is generated.

[0168] After the contour elements corresponding to the pre-sealing zone, pressure transmission zone, and unloading zone are combined with the mechanical seal contact requirement data and target operating condition data into a contact control analysis input dataset, the differential pressure control data, flushing control data, and venting control data are all formed based on the same group of zoning results and the same set of operating condition constraints.

[0169] S32 obtains differential pressure control data based on pre-sealing zone, mechanical seal contact requirement data, and target operating condition data.

[0170] Specifically, the lower limit of mechanical seal compression, the upper limit of mechanical seal compression, the lower limit of total clamping force, the upper limit of total clamping force, the lower limit of end face specific pressure, and the upper limit of end face specific pressure are read from the mechanical seal contact requirement data; the target head and the design density of the conveying medium are read from the target operating condition data; and the local extension direction and global path coordinates of each contour unit are read from the pre-sealing area.

[0171] First, determine the pressure change direction in the pre-sealing zone along the pressure transmission zone. Specifically, calculate the difference between the upper and lower limits of the mechanical seal compression, then divide the difference by the upper limit to obtain the compression fluctuation ratio. When the compression fluctuation ratio is not greater than the compression fluctuation ratio threshold, it is determined that the pressure change in the pre-sealing zone should maintain a unidirectional continuous change; when the compression fluctuation ratio is greater than the threshold, the pressure change direction is still calculated according to the unidirectional continuous change method, and a contact analysis verification mark is generated simultaneously.

[0172] The compression fluctuation ratio threshold is preferentially read from the compression stability control boundary in the mechanical seal technology sample; when the mechanical seal technology sample does not record this boundary separately, the ratio between the allowable fluctuation range of the mechanical seal compression and the upper limit of the mechanical seal compression is recorded as the compression fluctuation ratio threshold.

[0173] The profile element adjacent to the pressure transmission zone in the pre-sealing zone is selected as the end profile element for pressure delivery in the pre-sealing zone, and the profile element with the smallest global path coordinates in the pre-sealing zone is selected as the starting profile element for pressure delivery in the pre-sealing zone. The direction from the midpoint of the centerline of the starting profile element to the midpoint of the centerline of the end profile element in the pre-sealing zone is then defined as the pressure change direction. This direction definition ensures that the geometric change direction of the pre-sealing zone is consistent with the continuity direction of the pressure transmission zone.

[0174] Determine the allowable pressure variation range of the pre-sealing zone. Specifically, calculate the reference pressure value under operating conditions based on the design density of the conveying medium, standard gravitational acceleration, and target head. Then, calculate the ratio of the lower limit of the total clamping force to the upper limit of the end-face specific pressure, and the ratio of the upper limit of the total clamping force to the lower limit of the end-face specific pressure, to obtain the lower limit and upper limit of the effective end-face pressure area. When the lower limit of the effective end-face pressure area is not greater than the upper limit, the effective end-face pressure area range is deemed valid; when the lower limit of the effective end-face pressure area is greater than the upper limit, a contact analysis verification mark is generated.

[0175] Subsequently, the arithmetic mean of the lower limit and upper limit of the effective pressure area of ​​the end face is taken as the reference value of the effective pressure area of ​​the end face. Then, the lower limit and upper limit of the total clamping force are divided by the reference value of the effective pressure area of ​​the end face to obtain the lower limit and upper limit of the allowable pressure variation range of the pre-sealing zone. Finally, the consistency between the working condition reference pressure value and the allowable pressure variation range of the pre-sealing zone is checked. If the working condition reference pressure value is within the allowable pressure variation range, or if its deviation from the boundary of the allowable pressure variation range of the pre-sealing zone is not greater than the preset pressure deviation threshold, the allowable pressure variation range of the pre-sealing zone is determined to be valid; otherwise, a contact analysis verification mark is generated.

[0176] The preset pressure deviation threshold is pre-set based on the allowable pressure deviation range determined by the consistency of the pre-sealing zone operating conditions. This is to prevent the effective range from being discarded directly when the operating condition reference pressure slightly exceeds the limit due to local medium fluctuations.

[0177] Determine the pressure change prohibition zone in the pre-sealing area. Specifically, sequentially read the local extension direction of adjacent contour units in the pre-sealing area and calculate the angle between two adjacent local extension directions; when the angle is greater than the turning angle recognition threshold, the corresponding connection position is determined to be a turning part of the inner wall of the volute; when the angle is not greater than the turning angle recognition threshold, it is not determined to be a turning part.

[0178] The turning angle threshold is preset according to the recognition requirements of the influence of the geometric turning of the inner wall of the pre-sealing area on the local pressure distribution.

[0179] When a turning point is identified, the corresponding connection point of the turning point is used as the center, and a preset number of contour units are extended in both the direction of decreasing contour unit number and the direction of increasing contour unit number. This extended range is defined as the pressure change forbidden zone. When there are no expandable contour units in the adjacent direction, only the extended range in the existing direction is recorded. When there are multiple turning points, the multiple pressure change forbidden zones are merged.

[0180] The number of preset expansion units is preset according to the minimum coverage requirement of local pressure disturbances on both sides of the geometric transition.

[0181] By correlating the pressure change direction, the allowable pressure change range, and the prohibited pressure change range within the same region, differential pressure control data is obtained.

[0182] Specifically, a differential pressure control data table is established, which includes at least the following fields: pre-sealing zone profile unit field, pressure change direction field, allowable pressure change range field, pressure sudden change prohibited range field, and pre-sealing zone constraint status field.

[0183] For each contour unit in the pre-sealing area, its global path coordinates are determined to see if they fall within the pressure change prohibition zone. If a contour unit does not fall within the pressure change prohibition zone, and the angle between its local extension direction and the pressure change direction is not greater than a preset change direction deviation threshold, the contour unit is marked as a pre-sealing adjustable contour unit. If a contour unit falls within the pressure change prohibition zone, or the angle between its local extension direction and the pressure change direction is greater than the preset change direction deviation threshold, the contour unit is marked as a pre-sealing non-adjustable contour unit. The preset change direction deviation threshold is pre-set based on the allowable deviation range of the pressure change direction in the pre-sealing area.

[0184] When at least one adjustable profile element exists in the pre-sealing zone and the allowable pressure variation range is valid, the pressure change direction, allowable pressure variation range, prohibited pressure abrupt change range, and set of adjustable profile elements are written into the same differential pressure control record, and the pre-sealing zone constraint status is marked as available, thus obtaining differential pressure control data. When no adjustable profile element exists, or the allowable pressure variation range is invalid, a contact analysis verification mark is generated.

[0185] S33 obtains scour control data based on pressure transmission zone, mechanical seal contact requirement data, and target operating condition data.

[0186] Specifically, the lower limit and upper limit of the end face specific pressure are read from the mechanical seal contact requirement data; the target flow rate, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity and solid volume fraction are read from the target operating condition data; the local extension direction and source profile unit number of each profile unit are read from the pressure transmission zone; and the inner wall cross section of each pressure transmission zone is read from the inner wall cross section sequence of the pressure transmission zone.

[0187] Establish the correspondence between the upper limit of the end face specific pressure and the upper limit of the wall-attached flow velocity. The selection method for representative centrifugal pump prototypes is as follows: select from prototypes with the same number of stages and the same volute structure type as the centrifugal pump to be optimized; read the rated flow rate and rated head of each candidate prototype from the prototype parameter record, which comes from the prototype design task book, factory performance test report, or prototype performance curve record; calculate the rated flow deviation rate and rated head deviation rate of each candidate prototype, where the rated flow deviation rate is equal to the absolute value of the difference between the prototype rated flow rate and the target flow rate divided by the target flow rate, and the rated head deviation rate is equal to the absolute value of the difference between the prototype rated head and the target head divided by the target head; then sort the prototypes by their proximity index from smallest to largest, and select the top preset number of prototypes as representative centrifugal pump prototypes.

[0188] The number of preset prototypes is determined based on the requirements for the coverage of working conditions when establishing the correspondence between the upper limit of end face specific pressure and the upper limit of wall-attached flow velocity.

[0189] The prototype proximity index is equal to the preset flow rate weight multiplied by the rated flow rate deviation rate, plus the preset head weight multiplied by the rated head deviation rate; wherein, the preset flow rate weight and the preset head weight are preset according to the common evaluation requirements of flow condition similarity and head condition similarity.

[0190] After constructing the prototype proximity index by the rated flow deviation rate and rated head deviation rate, the selection of representative centrifugal pump prototypes no longer relies on empirical judgment, but directly converges around the main operating condition boundaries of the centrifugal pump to be optimized.

[0191] Prototype testing preferentially uses the target conveying medium body corresponding to the target operating condition data; when the target conveying medium body cannot be directly used, an equivalent test medium is used. The equivalent test medium must meet at least the following conditions: the deviation from the design density of the target conveying medium does not exceed a preset density deviation threshold, and the deviation of the operating condition reference pressure value formed under the target flow conditions does not exceed a preset operating condition pressure deviation threshold; when the target conveying medium is a high-viscosity medium, the equivalent test medium should also meet the requirement that the kinematic viscosity deviation does not exceed a preset viscosity deviation threshold; when the target conveying medium is a solid-containing medium, the equivalent test medium should also meet the requirement that the solid phase volume fraction deviation does not exceed a preset solid-containing deviation threshold; when the target conveying medium is a high-viscosity solid-containing medium, the equivalent test medium must simultaneously meet the constraints corresponding to the preset viscosity deviation threshold and the preset solid-containing deviation threshold.

[0192] The deviation thresholds are preset based on the comparability requirements of the operating conditions between the equivalent test medium and the target transport medium.

[0193] After constraining the equivalent test medium according to the design density, operating condition reference pressure, kinematic viscosity and solid volume fraction, the medium substitution relationship in the prototype test can simultaneously maintain the consistency of pressure level and the consistency of transport medium characteristics, so that the correspondence between the upper limit of end face specific pressure and the upper limit of wall-attached flow velocity can be reflected back to the current target transport medium operating conditions.

[0194] During the test, the wall-attached flow velocity in the pressure transmission zone of each representative centrifugal pump prototype was gradually increased, and a preset test holding time was maintained at each wall-attached flow velocity level. Whether continuous erosion marks appeared on the inner wall of the pressure transmission zone near the mechanical seal end face was recorded. The method for judging continuous erosion marks was as follows: after each wall-attached flow velocity test, the surface morphology of the corresponding inner wall test section of the pressure transmission zone was inspected. Detection points were arranged along the flow direction at preset detection point intervals, and the surface roughness increment of each detection point relative to the initial surface before the test was calculated. When the surface roughness increment of consecutive preset number of adjacent detection points along the flow direction was greater than the preset roughness increment threshold, continuous erosion marks were judged to have appeared; otherwise, continuous erosion marks were judged not to have appeared.

[0195] The preset test duration, preset detection point spacing, preset detection point number, and preset roughness increment threshold are preset according to the requirements of continuous erosion trace recognition for time stability, spatial resolution, and sensitivity to roughness changes.

[0196] By adopting the criterion that multiple consecutive detection points simultaneously exceed the roughness increment threshold, isolated detection errors can be distinguished from the real continuous scouring zone.

[0197] When no continuous scouring marks appear at a certain level of wall-attaching velocity, that level of wall-attaching velocity is recorded as the acceptable wall-attaching velocity. When continuous scouring marks appear at a certain level of wall-attaching velocity, the acceptable wall-attaching velocity of the previous level is recorded as the upper limit of the wall-attaching velocity under the corresponding upper limit of end-face specific pressure. The test results of all prototypes are then divided into multiple preset end-face specific pressure grade intervals according to the upper limit of end-face specific pressure, and the minimum upper limit of the wall-attaching velocity in each grade interval is taken and written into the corresponding relationship table.

[0198] The preset end-face pressure grading interval is determined based on the boundary of the change in the sensitivity of the mechanical seal end to the local high-speed wall-attached flow in the pressure transmission zone.

[0199] After dividing the upper limit of the end face specific pressure into multiple graded intervals, the upper limit of the wall-attached flow velocity can be called in layers according to different end face contact constraint levels, avoiding the sharing of the same scouring control upper limit by different end face specific pressure levels.

[0200] After the correspondence table is formed, the upper limit of the wall-attached flow velocity in the current pressure transmission zone is determined. Priority is given to reading the wall-attached flow velocity upper limit recorded individually in the mechanical seal technology sample; if not recorded, the corresponding wall-attached flow velocity upper limit is read from the correspondence table according to the preset end-face specific pressure grade interval where the end-face specific pressure upper limit value is located. After determining the upper limit of the wall-attached flow velocity in the current pressure transmission zone based on the minimum wall-attached flow velocity upper limit in each grade interval, the pressure transmission zone gradient screening and scouring control screening are both performed around the stricter flow velocity boundary of the corresponding grade interval.

[0201] The impact avoidance direction of the pressure transmission zone is then determined. Specifically, the contour unit with the smallest source contour unit number in the pressure transmission zone is taken as the inlet-side contour unit, and the contour unit with the largest source contour unit number is taken as the outlet-side contour unit; then, the direction from the midpoint of the centerline of the inlet-side contour unit to the midpoint of the centerline of the outlet-side contour unit is taken as the sequence direction of the pressure transmission zone. The angle between the sequence direction of the pressure transmission zone and the local extension direction of each pressure transmission zone contour unit is then calculated; when the angle is not greater than a preset homogeneous angle threshold, the corresponding local extension direction remains unchanged; when the angle is greater than the preset homogeneous angle threshold, the corresponding local extension direction is reversed.

[0202] The preset homing angle threshold is determined based on the requirements for the forward and reverse discrimination boundary in the homing process.

[0203] After the local extension direction has been normalized, the components of each unit direction vector are arithmetically averaged to obtain the average direction vector. This average direction vector is then normalized to obtain the impact avoidance direction. The target flow rate is used to confirm that the fluid in the pressure transmission zone is in a normal transport state from the inlet to the outlet. The local extension direction is used to ensure that the pressure transmission path on the inner wall of the volute is consistent with the overall fluid transport direction. Therefore, the unit direction vector after normalization is averaged and then normalized to obtain the impact avoidance direction.

[0204] The sequential order of pressure transmission zone changes is determined. Specifically, the cross-sections of the inner wall of the pressure transmission zone are first sorted from smallest to largest according to the source profile element numbers; then, the sorted order of the inner wall cross-sections is recorded as the sequential order of pressure transmission zone changes. When there is a missing number between two adjacent source profile element numbers, the sequential order of pressure transmission zone changes is considered interrupted, and a contact analysis verification mark is generated. The change of cross-sections in the pressure transmission zone should unfold along the direction of the fixed sequential numbering of the inner wall profile of the volute. Therefore, the order of the inner wall cross-sections in the pressure transmission zone is restored according to the source profile element numbering, and the sequential order of pressure transmission zone changes is determined accordingly.

[0205] The flow velocity upper limit, impact avoidance direction, and gradual change sequence are checked to obtain scour control data.

[0206] Specifically, a scour control data table is established, which includes at least the pressure transmission zone profile element field, the wall-attached flow velocity upper limit field, the impact avoidance direction field, the progressive continuous sequence field, and the pressure transmission zone constraint state field.

[0207] The cross-sections of the pressure transmission zones are read sequentially in a progressive order, and the estimated wall-attached velocity of the corresponding cross-section is calculated based on the target flow rate and the effective flow area of ​​each pressure transmission zone's inner wall cross-section. The effective flow area is the cross-sectional area of ​​the pressure transmission zone's inner wall cross-section that participates in the fluid flow; when the effective flow area is not directly recorded in the model, it is calculated based on the local flow area formed by the length of the cross-section line segment and the distance between adjacent cross-sections. The distance between adjacent cross-sections is the distance between the center point of the current pressure transmission zone's inner wall cross-section and the center point of the next pressure transmission zone's inner wall cross-section; when the current pressure transmission zone's inner wall cross-section is the last cross-section, the distance between it and the center point of the previous pressure transmission zone's inner wall cross-section is taken as the distance between adjacent cross-sections.

[0208] The inner wall cross-section of each pressure transmission zone is checked: if the estimated wall-attached velocity is not greater than the upper limit of the wall-attached velocity, and the angle between the local extension direction of the corresponding contour unit and the impact avoidance direction is not greater than the preset impact avoidance deviation threshold, the inner wall cross-section of the pressure transmission zone is marked as a qualified cross-section; otherwise, it is marked as a scour risk cross-section. The preset impact avoidance deviation threshold is pre-set based on the allowable deviation range of the impact avoidance direction from the extension direction of the inner wall of the pressure transmission zone.

[0209] When there are no numbering interruptions in the sequential progression and the number of qualified sections is not less than the preset minimum number of qualified sections, the upper limit of the wall-attached flow velocity, the impact avoidance direction, the sequential progression, and the set of qualified sections are written into the same scour control record to obtain scour control data. When there are numbering interruptions or the number of qualified sections is less than the preset minimum number of qualified sections, a contact analysis verification mark is generated.

[0210] S34 obtains exhaust control data based on unloading zone, mechanical seal contact requirement data, and target operating condition data.

[0211] Specifically, the lower limit of total clamping force, the upper limit of total clamping force, the lower limit of end face specific pressure, and the upper limit of end face specific pressure are read from the mechanical seal contact requirement data; the target flow rate, the target conveying medium type, the design density of the conveying medium, the design kinematic viscosity of the conveying medium, and the solid volume fraction are read from the target operating condition data; the local extension direction and the source contour unit number of each contour unit are read from the unloading zone; and the end inner wall cross section of each unloading zone is read from the unloading zone end inner wall cross section sequence.

[0212] First, determine the backflow retention and avoidance zone in the unloading area. Specifically, calculate the bandwidth of the total clamping force range and the bandwidth of the end face specific pressure range. Then, divide the bandwidth of the total clamping force range by the median value of the total clamping force range, and divide the bandwidth of the end face specific pressure range by the median value of the end face specific pressure range, respectively, to obtain the relative bandwidth of the total clamping force and the relative bandwidth of the end face specific pressure. When both are not greater than the preset relative bandwidth boundary threshold, the mechanical seal contact requirement is determined to be in a high-stability constraint state; otherwise, it is determined to be in a general-stability constraint state.

[0213] The preset relative bandwidth boundary threshold is preset according to the graded requirements of the allowable range of mechanical seal contact.

[0214] By separating the high-stability constraint state from the general-stability constraint state, the backflow avoidance interval can directly correspond to the width of the sealing contact constraint.

[0215] Establish the correspondence between stable constraint states and avoidance ratios. The selection of representative centrifugal pump prototypes adopts the same prototype proximity index and sorting rules as S33. Prototype tests prioritize the use of the target conveying medium body corresponding to the target operating condition data; when the target conveying medium body cannot be directly used, an equivalent test medium under the same conditions as S33 is used. For each representative centrifugal pump prototype, under the same target flow conditions, backflow retention avoidance tests are performed on multiple preset avoidance ratio ranges at the end of the unloading zone near the pressure transmission zone.

[0216] During the experiment, the local flow direction corresponding to each contour unit in the unloading zone was continuously sampled according to a preset sampling period, and it was counted whether there was a reverse flow vector that lasted for more than a preset number of sampling periods.

[0217] The multiple preset avoidance ratio ranges, preset sampling periods, and preset number of continuous sampling periods are preset according to the judgment requirements of the continuous export range at the end of the unloading zone based on the backflow retention identification.

[0218] The method for determining the reverse flow vector is as follows: Multiple velocity probes are arranged along the inner wall of the test section in the unloading zone according to the center position of each contour unit to collect the local flow velocity direction at the corresponding position of each contour unit; when the angle between the local flow velocity direction at a certain position and the end output direction is greater than the preset reverse determination angle threshold, the local flow velocity direction at that position is recorded as the reverse flow vector; wherein, the preset reverse determination angle threshold is preset according to the reverse determination boundary requirements between the local flow direction and the end output direction.

[0219] By adopting a rule that involves multiple sampling periods, the accidental interference of instantaneous vortices on the backflow determination can be avoided.

[0220] When, under a certain avoidance ratio, no reverse flow vector appears in any contour unit outside the avoidance interval for more than a number of consecutive sampling periods, the avoidance ratio is determined to meet the condition of no continuous backflow. Among all avoidance ratios that meet the condition of no continuous backflow, the smallest ratio is taken as the avoidance ratio under the corresponding stable constraint state.

[0221] Based on the correspondence between stable constraint states and clearance ratios, the backflow retention clearance ratio corresponding to the current mechanical seal contact requirements is determined. After classifying the mechanical seal contact constraint states according to relative bandwidth, the backflow retention clearance ratio can be applied in a tiered manner according to different contact stability levels, avoiding the sharing of the same unloading clearance range by different contact constraint levels.

[0222] When the mechanical seal contact requirement is a high stability constraint state, the range of continuous source contour units near the pressure transmission zone in the unloading zone is taken as the backflow retention avoidance interval according to the determined avoidance ratio corresponding to the high stability constraint state; when the mechanical seal contact requirement is a general stability constraint state, the range of continuous source contour units near the pressure transmission zone in the unloading zone is taken as the backflow retention avoidance interval according to the determined avoidance ratio corresponding to the general stability constraint state.

[0223] When the number of source contour units calculated proportionally is not an integer, it is rounded up; when the number of source contour units calculated proportionally is less than the preset minimum coverage unit number, it is determined according to the preset minimum coverage unit number; wherein, the preset minimum coverage unit number is preset according to the requirements of the minimum actual coverage range for the unloading area return avoidance identification.

[0224] By assigning different backflow retention and avoidance ratios to the high stability constraint state and the general stability constraint state, the adjustable range of the unloading zone can directly correspond to the width of the mechanical seal contact constraint. The stricter the mechanical seal contact constraint, the larger the backflow avoidance range retained in the unloading zone, thereby reducing the reverse impact of backflow at the unloading end on the mechanical seal contact state.

[0225] Determine the end-out direction of the unloading zone. Specifically, take the contour unit with the largest source contour unit number in the unloading zone as the end contour unit; then take the direction from the midpoint of the end contour unit's centerline to the geometric center point of the volute outlet section as the end-out direction; when the angle between the end-out direction and the normal direction of the volute outlet section is not greater than a preset threshold for the same-direction outgoing angle, the end-out direction is determined as the end-out direction; when the angle is greater than the preset threshold for the same-direction outgoing angle, the end-out direction is reversed and determined as the end-out direction.

[0226] The preset outgoing unidirectional angle threshold is preset according to the unidirectional discrimination requirement between the end outgoing direction and the normal direction of the volute exit section.

[0227] The determined end outlet direction serves as a reference for both determining the outlet outlet direction of the unloading zone and determining the flow stabilization.

[0228] Determine the open / close continuity sequence of the unloading zone. Specifically, sort the inner wall cross-sections at the end of the unloading zone from smallest to largest according to the source profile element number, and record the sorting result as the open / close continuity sequence; when there is a missing number between two adjacent source profile element numbers, it is determined that the open / close continuity sequence is interrupted, and a contact analysis verification mark is generated.

[0229] The backflow retention and avoidance interval, the end outlet direction, and the opening and dispersing sequence are checked to obtain the discharge control data.

[0230] Specifically, an exhaust control data table is established, which includes at least the following fields: unloading zone contour unit field, return flow retention and avoidance interval field, end-out direction field, opening and dispersing continuous sequence field, and unloading zone constraint status field.

[0231] The cross-sections of the inner wall at the end of the unloading zone are read sequentially in an open-closed, continuous order, and it is determined whether the contour unit corresponding to each end inner wall cross-section falls within the backflow retention and avoidance zone. For contour units that do not fall within the backflow retention and avoidance zone, the angle between their local extension direction and the end-out direction is calculated; when the angle is not greater than a preset end-out deviation threshold, the contour unit is marked as an exportable contour unit; when the angle is greater than the preset end-out deviation threshold, the contour unit is marked as an export deviation contour unit. The preset end-out deviation threshold is preset based on the allowable deviation range of the end-out direction of the unloading zone.

[0232] When the backflow retention and avoidance zone does not cover all contour units of the unloading zone, the opening and dispersing sequence has no numbering interruption, and at least one derivable contour unit exists, the backflow retention and avoidance zone, the end-out direction, the opening and dispersing sequence, and the set of derivable contour units are written into the same discharge control record to obtain discharge control data. When the backflow retention and avoidance zone covers all contour units of the unloading zone, or the opening and dispersing sequence has a numbering interruption, or there is no derivable contour unit, a contact analysis verification mark is generated.

[0233] S35, according to the spatial order of the pre-sealing zone, pressure transmission zone and unloading zone, integrates the differential pressure control data, flushing control data and dissipation control data with regional constraints to obtain contact control data.

[0234] Specifically, when differential pressure control data, flushing control data, and venting control data have all been generated and no contact analysis verification mark has been generated, a contact control data table is established. The contact control data table includes at least the following fields: area sequence field, area name field, area contour unit field, control data type field, control constraint field, constraint status field, and adjacent area connection field. The control constraint field is used to write the directional constraints, interval constraints, prohibited entry constraints, flow velocity constraints, sequence constraints, or avoidance constraints for the corresponding area. The constraint status field is used to indicate whether the corresponding area control record is available.

[0235] Following the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the first control record is written with the contour unit number, pressure change direction, allowable pressure change range, pressure sudden change prohibited range, and pre-sealing zone constraint status corresponding to the pre-sealing zone, and the control data type is marked as differential pressure control. Then, the second control record is written with the contour unit number, wall-attached flow velocity limit, impact avoidance direction, change sequence, and pressure transmission zone constraint status corresponding to the pressure transmission zone, and the control data type is marked as scouring control. Finally, the third control record is written with the contour unit number, backflow retention avoidance range, end-out direction, opening and dispersing sequence, and unloading zone constraint status corresponding to the unloading zone, and the control data type is marked as dissipation control.

[0236] After the three control records are written, the adjacent areas are checked for continuity. The continuity check includes: checking whether the maximum contour unit number of the pre-sealing area is less than the minimum contour unit number of the pressure transmission area, and checking whether the maximum contour unit number of the pressure transmission area is less than the minimum contour unit number of the unloading area; when the above numbering relationship is true, the pre-sealing area to the pressure transmission area and the pressure transmission area to the unloading area are marked as continuity; when any numbering relationship is false, a contact analysis verification mark is generated.

[0237] When the adjacent area acceptance verification is passed, the first control record, the second control record, and the third control record are written into the same contact control record to obtain contact control data. The pre-sealing zone control field in the contact control data is used for extracting pre-sealing adjustment data, the pressure transmission zone control field is used for extracting pressure transmission adjustment data, and the unloading zone control field is used for extracting unloading adjustment data. Therefore, the contact control data is not a parallel record of differential pressure control data, flushing control data, and discharge control data, but rather a unified control record with regional acceptance relationships formed according to the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone.

[0238] If any of the differential pressure control data, flushing control data, or venting control data is missing, or if the adjacent area connection verification fails, the contact control data will not be written; only the contact analysis verification mark and the corresponding reason will be recorded.

[0239] Step S4: Based on the pre-sealing zone, pressure transmission zone, unloading zone, contact control data, and volute structure data, extract the flow channel adjustment items to obtain the regional adjustment data.

[0240] S41, read the corresponding contour units from the pre-sealing zone, pressure transmission zone and unloading zone respectively, read the differential pressure control record corresponding to the pre-sealing zone, the flushing control record corresponding to the pressure transmission zone and the discharge control record corresponding to the unloading zone from the contact control data, and read the volute inner wall contour data and volute outlet position data from the volute structure data to obtain the regional adjustment term extraction input dataset.

[0241] Specifically, the corresponding contour unit numbers, local extension directions, contour unit coordinates, and global path coordinates are read from the pre-sealing zone, pressure transmission zone, and unloading zone, respectively. Differential pressure control data, scouring control data, and venting control data are read from the contact control data. The volute inner wall contour data and volute outlet position data are read from the volute structure data. When the pre-sealing zone, pressure transmission zone, and unloading zone are all non-empty, the differential pressure control data, scouring control data, and venting control data have all been formed, and the volute inner wall contour data and volute outlet position data exist simultaneously, the input dataset for the region adjustment item extraction is deemed valid; otherwise, an adjustment extraction verification mark is generated.

[0242] S42 obtains pre-sealing adjustment data based on pre-sealing zone, differential pressure control data, and volute structure data.

[0243] Specifically, the contour unit number, starting coordinates, ending coordinates, and local extension direction of each contour unit are read from the pre-sealing area; the pressure change direction, allowable pressure change range, and prohibited pressure change range are read from the differential pressure control data.

[0244] Identify the volute transition area in the pre-sealing region. Specifically, sequentially read two adjacent contour units in the pre-sealing region and calculate the angle between their local extension directions. When the angle is not less than the transition area identification angle threshold, the corresponding connection position is identified as the volute transition area. When the angle is less than the transition area identification angle threshold, it is not identified as the volute transition area.

[0245] The transition part identification angle threshold is obtained by acquiring the angle fluctuation record between the local extension directions of adjacent contour units in the continuous smooth inner wall segment of the pre-sealing area, and determining the maximum allowable directional fluctuation value of the continuous smooth inner wall segment as the transition part identification angle threshold, so as to distinguish the small discrete directional fluctuation from the real transition part.

[0246] When no transition part of the volute is identified in the pre-sealing area, the connection position of the outline unit number in the pre-sealing area is taken as the alternative transition part, and an adjustment extraction verification mark is generated. After adopting this processing method, when the overall transition of the pre-sealing area is relatively smooth, the minimum identification benchmark for extracting the transition width and turning position can still be formed.

[0247] After the volute transition area is formed, it is screened. Specifically, all volute transition areas are first sorted according to the contour unit number, and then volute transition areas located within the pressure change prohibition zone are removed. Then, the lower and upper limits of the allowable pressure change range are read, the allowable pressure change range bandwidth is calculated, and the bandwidth is divided by the upper limit of the allowable pressure change range to obtain the allowable range bandwidth ratio. When the allowable range bandwidth ratio is not greater than the range bandwidth ratio boundary threshold, the pressure control in the pre-sealing area is determined to be in a narrow range constraint state; when the allowable range bandwidth ratio is greater than the range bandwidth ratio boundary threshold, it is determined to be in a general range constraint state.

[0248] The interval bandwidth ratio boundary threshold is obtained by: determining the interval bandwidth ratio boundary value between the narrow interval constraint state and the general interval constraint state based on the graded requirements of the pre-sealing area pressure control for the allowable pressure change interval, and determining this boundary value as the interval bandwidth ratio boundary threshold.

[0249] When the pressure control in the pre-sealing zone is in a narrow-range constraint state, only the volute transition part with an included angle not greater than the upper limit of the narrow-range turning angle is retained; when the pressure control in the pre-sealing zone is in a general-range constraint state, only the volute transition part with an included angle not greater than the upper limit of the general-range turning angle is retained.

[0250] The upper limit of the narrow interval turning angle and the upper limit of the general interval turning angle are obtained by: obtaining test records of the volute transition angle under different pre-sealing pressure control states, statistically analyzing the upper limit of the transition angle that can still maintain continuous pressure change under the corresponding pressure control state, and determining the upper limit of the transition angle corresponding to the stricter pressure control state as the upper limit of the narrow interval turning angle, and determining the upper limit of the transition angle corresponding to the general pressure control state as the upper limit of the general interval turning angle.

[0251] By differentiating the pressure control status of the pre-sealing zone according to the allowable interval bandwidth ratio, and filtering the transition part of the volute according to the corresponding upper limit of the turning angle, the angle of the transition part in the pre-sealing adjustment data can directly correspond to the allowable pressure range of the pre-sealing zone.

[0252] The volute transition region that remains after removing the pressure mutation forbidden zone and filtering the upper limit of the turning angle is determined as the target volute transition region.

[0253] Based on the allowable pressure variation range, the transition width and turning position are constrained and matched to obtain pre-sealing adjustment data. Specifically, the transition width and turning position are extracted for the target volute transition section; when the turning position is outside the pressure mutation prohibition range and the pressure change in the pre-sealing area corresponding to the transition width falls within the allowable pressure variation range, the transition width, turning position, source number, and global path coordinates of the target volute transition section are written into the pre-sealing adjustment data table to obtain pre-sealing adjustment data; when the turning position falls within the pressure mutation prohibition range, or the corresponding pressure change exceeds the allowable pressure variation range, the target volute transition section is removed.

[0254] S43 obtains pressure adjustment data based on pressure transmission zone, scour control data, and volute structure data.

[0255] Specifically, the contour unit number, starting coordinates, ending coordinates, and local extension direction of each contour unit are read from the pressure transmission zone; the upper limit of the wall-attached flow velocity, the impact avoidance direction, and the sequential change are read from the scouring control data.

[0256] Extract the inner wall cross sections of the pressure transmission zone in a progressive and continuous sequence, and determine the connecting section between two adjacent inner wall cross sections of the pressure transmission zone as the progressive section of the volute cross section; when the number of inner wall cross sections of the pressure transmission zone is less than the preset minimum number of cross sections, no progressive section of the volute cross section is formed, and an adjustment extraction verification mark is generated.

[0257] The method for obtaining the preset minimum cross-section number is as follows: based on the formation requirements of the transitional part of the volute cross-section, it is determined that at least one connecting section should be defined by the inner wall cross-sections of two adjacent pressure transmission zones, and the corresponding minimum cross-section number is determined as the preset minimum cross-section number.

[0258] After the graded sections of the volute cross section are formed, they are screened. Specifically, all graded sections of the volute cross section are sorted in the order of continuous graded change, and the local graded change direction corresponding to each graded section is calculated. When the angle between the local graded change direction and the impact avoidance direction is not greater than the direction deviation threshold, the graded section of the volute cross section is retained; when the angle is greater than the direction deviation threshold, the graded section of the volute cross section is removed.

[0259] Check whether the retained volute cross-section transition parts meet the transition continuity order; when the sorting numbers of two adjacent volute cross-section transition parts are consecutive, it is determined that the transition continuity order is met; when the sorting numbers of two adjacent volute cross-section transition parts are not consecutive, the volute cross-section transition parts with interrupted order are removed, and an adjustment extraction verification mark is generated.

[0260] The selection criteria for the changing rhythm are determined based on the upper limit of the wall-attached velocity. When the upper limit of the wall-attached velocity is not greater than the velocity state boundary threshold, the velocity constraint in the pressure transmission zone is determined to be in a strict state; when the upper limit of the wall-attached velocity is greater than the velocity state boundary threshold, the velocity constraint in the pressure transmission zone is determined to be in a general state. The arithmetic mean of the distance between the center points of the inner wall sections of all adjacent pressure transmission zones is calculated. When the velocity constraint in the pressure transmission zone is in a strict state, only the changing parts of the volute section where the distance between the center points of the inner wall sections of adjacent pressure transmission zones is not greater than the product of the preset strict rhythm ratio and the arithmetic mean are retained; when the velocity constraint in the pressure transmission zone is in a general state, only the changing parts of the volute section where the distance between the center points of the inner wall sections of adjacent pressure transmission zones is not greater than the product of the preset general rhythm ratio and the arithmetic mean are retained.

[0261] The volute cross-section gradient parts retained after direction screening, gradient continuity sequence screening, and gradient rhythm screening are determined as the target volute cross-section gradient parts.

[0262] Based on the continuous progression sequence, the direction and rhythm of cross-sectional progression are matched for continuity to obtain pressure transmission adjustment data. Specifically, the progressive parts of the target volute cross-section are sorted according to the continuous progression sequence, and the source sequence numbers of adjacent progressive parts of the target volute cross-section are checked for continuity. When the source sequence numbers are continuous and the angle between the progressive directions of adjacent cross-sections is not greater than a preset continuous threshold for progressive directions, the corresponding progressive direction of the cross-section is determined to meet the continuity requirement. When the source sequence numbers are not continuous, or the angle between the progressive directions of adjacent cross-sections is greater than the preset continuous threshold for progressive directions, the progressive parts of the target volute cross-section with interrupted sequence are removed. For the retained progressive parts of the target volute cross-section, their local progressive direction is determined as the cross-sectional progressive direction, and the Euclidean distance between the center points of the inner wall cross-sections of the corresponding two adjacent pressure transmission zones is determined as the progressive rhythm. The cross-sectional progressive direction, progressive rhythm, source sequence number, and global path coordinates are extracted and written into the pressure transmission adjustment data table to obtain the pressure transmission adjustment data.

[0263] S44 obtains unloading adjustment data based on unloading zone, exhaust control data, and volute structure data.

[0264] Specifically, the contour unit number, starting coordinates, ending coordinates, and local extension direction of each contour unit are read from the unloading zone; the return flow retention avoidance zone, end outlet direction, and opening and dispersing sequence are read from the discharge control data; and the volute outlet position data are read from the volute structure data.

[0265] Extract the inner wall section of the unloading zone end in an open-closed continuous sequence, and determine the connecting section between two adjacent inner wall sections of the unloading zone end as the volute exit section; when the number of inner wall sections of the unloading zone end is less than the preset minimum number of end sections, the volute exit section is not formed, and an adjustment extraction verification mark is generated; wherein, the preset minimum number of end sections is obtained by: determining, according to the formation requirements of the volute exit section, that at least one connecting section should be defined by two adjacent inner wall sections of the unloading zone end, and determining the corresponding minimum number of end sections as the preset minimum number of end sections.

[0266] After the volute exit sections are formed, they are screened. Specifically, all volute exit sections are first sorted in an open-and-closed continuous order, and then each exit section is checked to see if it is located within the reflux retention and avoidance zone. If a volute exit section falls into the reflux retention and avoidance zone, it is removed; if it does not fall into the reflux retention and avoidance zone, it is retained. The angle between the local exit direction and the terminal exit direction of each retained volute exit section is calculated, and this angle is determined as the exit deviation angle. If the exit deviation angle is not greater than the exit direction deviation threshold, the volute exit section is retained; if the exit deviation angle is greater than the exit direction deviation threshold, the volute exit section is removed.

[0267] The method for obtaining the export direction deviation threshold is as follows: obtain the export direction adjustment test record of the unloading area, count the maximum allowable export deviation angle under the condition of meeting the end export requirements, and determine the maximum value as the export direction deviation threshold.

[0268] Check whether the retained volute exit parts meet the open-closed continuous sequence. If the sorting numbers of two adjacent volute exit parts are consecutive, it is determined that the open-closed continuous sequence is met. If the sorting numbers of two adjacent volute exit parts are not consecutive, the volute exit parts with interrupted sequence are removed, and an adjustment extraction verification mark is generated. After superimposing the backflow avoidance screening and the exit direction screening, the retained volute exit parts simultaneously meet the backflow avoidance requirements and the end exit direction requirements.

[0269] The volute exit portion that is retained after filtering by backflow avoidance, exit direction, and opening and closing sequence is determined as the target volute exit portion.

[0270] For the exit section of the target volute, its local exit direction is determined as the exit exit direction. Then, following the opening and closing sequence from smallest to largest, the end closer to the geometric center point of the volute exit section is defined as the exit side, and the end farther from the geometric center point of the volute exit section is defined as the inlet side. Each target volute exit section is jointly defined by the outlet side endpoint of the inner wall section at the end of the previous unloading zone and the inlet side endpoint of the inner wall section at the end of the next unloading zone. Subsequently, the Euclidean distances from the two endpoints to the geometric center point of the volute exit section are calculated, and the coordinates of the endpoint with the smaller distance are determined as the end opening position. When the two distances are the same, the coordinates of the endpoint with the larger source contour element number are taken as the end opening position. The Euclidean distance from the end opening position to the geometric center point of the volute exit section is then recorded as the end opening exit distance.

[0271] Based on the continuous sequence of opening and dispersing, the outlet discharge direction and the terminal opening and dispersing position are matched to obtain the unloading adjustment data.

[0272] Specifically, the target volute exit sections are sorted according to the order of opening and closing continuity, and the source sequence numbers of adjacent target volute exit sections are checked for continuity. When the source sequence numbers are continuous and the included angle between adjacent exit directions is not greater than a preset threshold for continuity of exit directions, the corresponding target volute exit section is determined to meet the exit connection requirements; otherwise, target volute exit sections with interrupted sequence are removed. For the retained target volute exit sections, the exit direction, end opening and closing position, end opening and closing exit distance, source sequence number, and global path coordinates are extracted and written into the unloading adjustment data table to obtain unloading adjustment data.

[0273] S45, according to the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data are partitioned and connected to obtain regional adjustment data.

[0274] Specifically, when pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data have all been generated and no adjustment extraction verification mark has been generated, a regional adjustment data table is established. The regional adjustment data table includes at least the following fields: regional sequence field, regional name field, adjustment data field, source sequence number field, global path coordinate field, and adjacent adjustment succession field.

[0275] Following the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing adjustment data is first written to the pre-sealing zone adjustment field, then the pressure transmission adjustment data is written to the pressure transmission zone adjustment field, and finally the unloading adjustment data is written to the unloading zone adjustment field. Subsequently, the three adjustment fields are checked for connectivity: if the global path coordinates of the pre-sealing adjustment data are less than the global path coordinates of the pressure transmission adjustment data, and the global path coordinates of the pressure transmission adjustment data are less than the global path coordinates of the unloading adjustment data, then the three are deemed to satisfy the partition connectivity relationship; otherwise, an adjustment extraction verification mark is generated.

[0276] When multiple pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data exist, they are first sorted in ascending order of global path coordinates. Each pressure transmission adjustment data is used as an intermediate reference record. The pre-sealing adjustment data whose global path coordinates are located before this intermediate reference record and are closest to it is used as the front-end connection record. The unloading adjustment data whose global path coordinates are located after this intermediate reference record and are closest to it is used as the end-end connection record. Each pre-sealing adjustment data and each unloading adjustment data can only be used once in the same round of partition connection arrangement. When a front-end connection record, intermediate reference record, and end-end connection record exist simultaneously, and their global path coordinates sequentially satisfy the condition that the pre-sealing adjustment data is less than the pressure transmission adjustment data, and the pressure transmission adjustment data is less than the unloading adjustment data, all three are written into the same regional adjustment record. If any record is missing or the global path coordinates do not satisfy the spatial order, no regional adjustment record is formed, and an adjustment extraction and verification mark is generated. All regional adjustment records are written into the regional adjustment data table to obtain the regional adjustment data. Each regional adjustment record in the regional adjustment data includes pre-sealing zone adjustment fields, pressure transmission zone adjustment fields, and unloading zone adjustment fields, enabling subsequent flow path sequence corrections to compare the continuity of the front-end transition, pressure transmission variation, and end-end output around the same record.

[0277] Step S5: Based on the regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data, the flow channel sequence is corrected to obtain the target flow channel parameters.

[0278] S51 reads pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data from the regional adjustment data; reads differential pressure control data, flushing control data, and dispersion control data from the contact control data; reads impeller outlet position data and impeller outlet direction data from the impeller outlet structure data; and reads target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid phase volume fraction, allowable value of mechanical seal leakage, and allowable value of whole machine vibration amplitude from the target operating condition data to obtain the flow channel sequence correction input dataset.

[0279] Specifically, pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data are read from the regional adjustment data. Pre-sealing adjustment data includes at least the transition width, turning point, source number, and global path coordinates. Pressure transmission adjustment data includes at least the cross-sectional change direction, change rhythm, source number, and global path coordinates. Unloading adjustment data includes at least the outlet discharge direction, end opening / dispersion position, end opening / dispersion outlet distance, source number, and global path coordinates. Then, differential pressure control data, scouring control data, and exhaust control data are read from the contact control data. Impeller outlet position data and impeller outlet direction data are read from the impeller outlet structure data. Target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, allowable mechanical seal leakage, and allowable overall machine vibration amplitude are read from the target operating condition data.

[0280] Then, a pre-correction check is performed: when the pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data have all been generated, and the differential pressure control data, flushing control data, and dispersion control data have all been generated, and the impeller outlet position data, impeller outlet direction data, target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid phase volume fraction, mechanical seal leakage allowable value, and overall machine vibration amplitude allowable value all exist, the flow channel sequence correction input dataset is determined to be valid; otherwise, a sequence correction verification mark is generated.

[0281] S52, based on the area adjustment data and contact control data, performs flow channel sequence correction to obtain a set of candidate flow channel parameters.

[0282] Specifically, the transition width, turning point, source number, and global path coordinates corresponding to the transition part of the target volute are read from the pre-sealing adjustment data; the cross-sectional change direction, change rhythm, source number, and global path coordinates corresponding to the cross-sectional change part of the target volute are read from the pressure transmission adjustment data; and the outlet discharge direction, terminal opening and closing position, terminal opening and closing outlet distance, source number, and global path coordinates corresponding to the outlet part of the target volute are read from the unloading adjustment data. Then, the pressure change direction, allowable pressure change range, and pressure sudden change prohibited range are read from the differential pressure control data; the wall-attached flow velocity limit, impact avoidance direction, and change continuity sequence are read from the scour control data; and the backflow retention avoidance range, terminal discharge direction, and opening and closing continuity sequence are read from the discharge control data.

[0283] Based on the differential pressure control data, the pre-sealing adjustment data is corrected to obtain pre-sealing corrected data. Specifically, the lower and upper limits of the allowable pressure change range are first read, and the allowable pressure change range bandwidth is calculated. Then, the allowable pressure change range bandwidth is divided by the upper limit of the allowable pressure change range to obtain the pre-sealing corrected bandwidth ratio. When the pre-sealing corrected bandwidth ratio is not greater than the pre-sealing corrected state boundary threshold, the pre-sealing pressure control is determined to be in a strict correction state; when the pre-sealing corrected bandwidth ratio is greater than the pre-sealing corrected state boundary threshold, the pre-sealing pressure control is determined to be in a general correction state.

[0284] The pre-sealing correction state boundary threshold is obtained by determining the bandwidth ratio boundary between the strict correction state and the general correction state based on the graded requirements of the pre-sealing zone pressure control for the allowable pressure change range, and then determining this boundary value as the pre-sealing correction state boundary threshold.

[0285] When the pre-sealing pressure is controlled in a strictly corrected state, the original transition width of each volute transition part is multiplied by the strict correction width ratio to obtain the corrected transition width; when the pre-sealing pressure is controlled in a normal correction state, the original transition width of each volute transition part is multiplied by the normal correction width ratio to obtain the corrected transition width.

[0286] The methods for obtaining the strict correction width ratio and the general correction width ratio are as follows: Obtain the pre-sealing width correction test records of the prototype, statistically analyze the transition width correction ratios that maintain a smooth pressure change under both strict and general correction states, and determine the corresponding ratios as the strict correction width ratio and the general correction width ratio, respectively. The stricter the pressure control in the pre-sealing area, the smaller the local transition scale should be to maintain a smooth pressure change; therefore, the strict correction width ratio corresponding to the strict correction state is smaller than the general correction width ratio corresponding to the general correction state.

[0287] Check whether each turning point falls within the pressure change forbidden zone; if a turning point does not fall within the pressure change forbidden zone, keep the turning point unchanged; if a turning point falls within the pressure change forbidden zone, move the turning point along the pressure change direction by a preset correction step size to obtain a corrected turning point. The preset correction step size is the distance between the midpoints of the center lines of adjacent contour units before and after the current turning point; when there are only one side of adjacent contour units, the distance between the midpoint of the center line of that one side of adjacent contour units and the midpoint of the center line of the current contour unit is taken as the preset correction step size.

[0288] The corrected turning point after the movement is re-evaluated: if the corrected turning point still falls within the pressure change forbidden zone, the movement continues along the pressure change direction by a preset correction step size; if the corrected turning point moves out of the pressure change forbidden zone, the movement ends; if the number of consecutive movements reaches the preset maximum number of corrections, and the corrected turning point still falls within the pressure change forbidden zone, or if the movement has exceeded the range of the corresponding source contour unit in the pre-sealing area, a sequential correction verification mark is generated, and the pre-sealing correction record is marked as invalid.

[0289] The preset maximum number of corrections is obtained by determining the maximum number of consecutive movements allowed for local corrections based on the minimum removal requirements of the local correction on the current restricted position and its adjacent affected positions, and then setting this maximum number of consecutive movements as the preset maximum number of corrections. With this rule, pre-closure corrections are always limited to the current local influence range and do not extend to cross-regional reconstruction.

[0290] Finally, the original transition width, the corrected transition width, the corrected turning point, the source sequence number, and the global path coordinates are recorded to obtain the pre-sealing correction data.

[0291] Based on the scouring control data, the pressure transmission adjustment data is corrected to obtain the corrected pressure transmission data. Specifically, the angle between the transition direction of each section and the impact avoidance direction is calculated, and this angle is determined as the transition deviation angle. When the transition deviation angle is not greater than the transition direction deviation threshold, the transition direction of that section remains unchanged. When the transition deviation angle is greater than the transition direction deviation threshold, the transition direction of that section is rotated around the center point of the corresponding section towards the impact avoidance direction until the transition deviation angle equals the transition direction deviation threshold, thus obtaining the corrected transition direction of the section.

[0292] The method for obtaining the gradient direction deviation threshold is as follows: obtain the flow direction correction test record of the pressure transmission zone, count the maximum allowable value of the gradient deviation angle under the condition of meeting the impact avoidance requirements, and determine the maximum value as the gradient direction deviation threshold.

[0293] The rhythm is adjusted based on the upper limit of the wall-attached flow velocity. When the upper limit of the wall-attached flow velocity is not greater than the threshold of the flow velocity adjustment state, the original rhythm is multiplied by the strict rhythm adjustment ratio to obtain the adjusted rhythm. When the upper limit of the wall-attached flow velocity is greater than the threshold of the flow velocity adjustment state, the original rhythm is multiplied by the general rhythm adjustment ratio to obtain the adjusted rhythm.

[0294] The method for obtaining the flow rate correction state boundary threshold is as follows: obtain the test record of the wall-attached flow rate control in the pressure transmission zone, count the upper limit boundary value of the wall-attached flow rate when the rate of change needs to be significantly tightened, and determine the boundary value as the flow rate correction state boundary threshold.

[0295] The strict rhythm correction ratio and the general rhythm correction ratio are obtained as follows: Test records of the variable rhythm correction in the pressure transmission section of the prototype are acquired; the variable rhythm correction ratios that maintain scour control requirements under strict flow velocity constraints and general flow velocity constraints are statistically analyzed; and the corresponding ratios are determined as the strict rhythm correction ratio and the general rhythm correction ratio, respectively. The stricter the flow velocity constraint against the wall, the greater the contraction of the variable rhythm, thereby compressing the local space for accumulated impact against the wall.

[0296] Finally, the original variation rhythm, the variation direction of the corrected section, the corrected variation rhythm, the source sequence number, and the global path coordinates are recorded to obtain the pressure transmission correction data.

[0297] Based on the discharge control data, the discharge adjustment data is corrected to obtain the corrected discharge data. Specifically, the angle between the discharge direction of each outlet and the final discharge direction is calculated and determined as the discharge deviation angle. When the discharge deviation angle is not greater than the discharge direction deviation threshold, the discharge direction of the outlet remains unchanged. When the discharge deviation angle is greater than the discharge direction deviation threshold, the discharge direction of the outlet is rotated around the center point of the corresponding discharge part toward the final discharge direction until the discharge deviation angle is equal to the discharge direction deviation threshold, thus obtaining the corrected discharge direction of the outlet.

[0298] The method for obtaining the export direction deviation threshold is as follows: obtain the export direction adjustment test record of the unloading area, count the maximum allowable export deviation angle under the condition of meeting the end export requirements, and determine the maximum value as the export direction deviation threshold.

[0299] Check whether each end-spreading position falls within the reflux retention and avoidance zone; if an end-spreading position does not fall within the reflux retention and avoidance zone, keep that end-spreading position unchanged; if an end-spreading position falls within the reflux retention and avoidance zone, move that end-spreading position along the continuous spread sequence towards the volute outlet direction by a preset lead-out correction step length to obtain the corrected end-spreading position. The preset lead-out correction step length is the distance between the center point of the current lead-out part and the center point of the next lead-out part; when there is no next lead-out part, take the distance between the center point of the current lead-out part and its corresponding end-spreading position as the preset lead-out correction step length.

[0300] The correction end divergence position after movement is re-evaluated: if the correction end divergence position still falls within the reflux retention avoidance zone, continue moving along the divergence sequence towards the volute outlet direction with a preset correction step size; if the correction end divergence position moves out of the reflux retention avoidance zone, the movement ends; if the number of consecutive movements reaches the preset maximum correction number, and the correction end divergence position still falls within the reflux retention avoidance zone, or if the movement has exceeded the range of the corresponding source contour unit of the unloading zone, a sequence correction verification mark is generated, and the unloading correction record is marked as invalid.

[0301] The preset maximum number of corrections is consistent with the preset maximum number of corrections used in the pre-sealing correction, so that the correction of the unloading zone is also limited to the local outlet section.

[0302] Finally, the corrected outlet direction, corrected terminal divergence position, source number, and global path coordinates are recorded to obtain the offflow correction data.

[0303] Following the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing correction data, pressure transmission correction data, and unloading correction data are connected and arranged in the flow channel segment to obtain a set of candidate flow channel parameters.

[0304] Specifically, using the pressure transmission correction data as the intermediate reference record set, and following the one-to-one pairing rule of the nearest neighbor of global path coordinates, the pre-sealing correction record that is located before the pressure transmission correction data and is the closest to it is selected from the pre-sealing correction data, and the unloading correction record that is located after the pressure transmission correction data and is the closest to it is selected from the unloading correction data. Each pre-sealing correction record and each unloading correction record are only allowed to be paired once in the same turntable connection arrangement.

[0305] When the same pressure transmission correction record can be matched with both the pre-sealing correction record and the unloading correction record, and the global path coordinates of the three records satisfy the condition that the pre-sealing correction record is less than the pressure transmission correction record and the pressure transmission correction record is less than the unloading correction record, the three records will be arranged into a candidate flow channel parameter unit. When the pre-sealing correction record and the unloading correction record cannot be matched simultaneously, or the global path coordinates of the three records do not satisfy the spatial order, a candidate flow channel parameter unit will not be formed, and a sequence correction verification mark will be generated.

[0306] All candidate flow channel parameter units are written into the candidate flow channel parameter set table to obtain the candidate flow channel parameter set. Each candidate flow channel parameter unit includes a pre-sealing correction field, a pressure transmission correction field, and a flow discharge correction field, which are used for subsequent transition continuity screening, contact control screening, and operating condition adaptation screening.

[0307] Specifically, using the pressure transmission correction data as the intermediate reference record set, and following the one-to-one pairing rule of the nearest neighbor of global path coordinates, the pre-sealing correction record that is located before the pressure transmission correction data and is the closest to it is selected from the pre-sealing correction data, and the unloading correction record that is located after the pressure transmission correction data and is the closest to it is selected from the unloading correction data. Each pre-sealing correction record and each unloading correction record are only allowed to be paired once in the same turntable connection arrangement.

[0308] When the same pressure transmission correction record can be matched with both the pre-sealing correction record and the unloading correction record, and the global path coordinates of the three records satisfy the condition that the pre-sealing correction record is less than the pressure transmission correction record and the pressure transmission correction record is less than the unloading correction record, the three records will be arranged into a candidate flow channel parameter unit. When the pre-sealing correction record and the unloading correction record cannot be matched simultaneously, or the global path coordinates of the three records do not satisfy the spatial order, a candidate flow channel parameter unit will not be formed, and a sequence correction verification mark will be generated.

[0309] All candidate flow channel parameter units are written into the candidate flow channel parameter set table to obtain the candidate flow channel parameter set. Each candidate flow channel parameter unit includes a pre-sealing correction field, a pressure transmission correction field, and a flow discharge correction field, which are used for subsequent transition continuity screening, contact control screening, and operating condition adaptation screening.

[0310] S53, based on the impeller outlet structure data and volute structure data, the candidate flow channel parameter set is screened for transition continuity to obtain the first candidate flow channel parameter set.

[0311] Specifically, the impeller outlet position data and impeller outlet direction data are read from the impeller outlet structure data, the end-out direction in the exhaust control data is read from the contact control data, and the pre-sealing correction field, pressure transmission correction field and unloading correction field corresponding to each candidate flow channel parameter unit are read from the candidate flow channel parameter set.

[0312] For each candidate flow channel parameter unit, the following parameters are extracted: corrected turning point and corrected transition width from the pre-sealing correction field; corrected cross-sectional change direction and corrected change rhythm from the pressure transmission correction field; and corrected outlet exit direction, corrected end divergence position, and end divergence outlet distance from the unloading correction field. The corrected transition width, corrected change rhythm, and end divergence outlet distance are considered auxiliary correction parameters and are checked sequentially along with the global path coordinates, but are not separately included in the directional continuity angle calculation. A continuity evaluation chain is then constructed, which includes at least the impeller outlet direction, the line connecting the geometric center point corresponding to the impeller outlet position data to the corrected turning point, the corrected cross-sectional change direction, the corrected outlet exit direction, and the end exit direction. The angle between adjacent directional quantities in the continuity evaluation chain is then calculated and determined as the continuity connection angle. If all continuity connection angles are not greater than the transition continuity angle threshold, the candidate flow channel parameter unit is deemed to meet the transition continuity requirements; otherwise, it is discarded.

[0313] The transition continuity angle threshold is obtained by acquiring the flow channel sequence correction continuity test record, statistically analyzing the maximum allowable continuity connection angle between adjacent directions under the condition of maintaining continuous connection between the impeller outlet, pre-sealing zone, pressure transmission zone and unloading zone, and determining the maximum continuity connection angle as the transition continuity angle threshold.

[0314] By incorporating the end-out direction into the continuity evaluation chain, the continuity judgment of candidate flow channel parameters not only covers the front and middle sections from the impeller outlet to the pressure transmission zone, but also the outgoing connection relationship at the unloading end, thus enabling the outlet-end outgoing continuity to be uniformly screened before entering the working condition adaptation screening.

[0315] Based on the global path coordinates attached to the pre-sealing correction field, pressure transmission correction field, and unloading correction field, check whether the global path coordinates maintain a monotonic progression from the pre-sealing area to the pressure transmission area and then to the unloading area. If the monotonic progression is maintained, the candidate flow channel parameter unit is determined to meet the sequential continuity requirement; otherwise, it is discarded. Finally, the candidate flow channel parameter units that have passed the transition continuity screening are written into the first candidate flow channel parameter set table to obtain the first candidate flow channel parameter set.

[0316] S54, based on the contact control data, perform contact control screening on the first candidate flow channel parameter set to obtain the second candidate flow channel parameter set.

[0317] Specifically, differential pressure control data, flushing control data, and discharge control data are read from the contact control data, and the pre-sealing correction field, pressure transmission correction field, and unloading correction field corresponding to each candidate flow channel parameter unit are read from the first candidate flow channel parameter set.

[0318] First, differential pressure control screening is performed. The allowable pressure variation range and the prohibited pressure abrupt change range are read from the differential pressure control data. The original transition width and corrected transition width corresponding to each candidate flow channel parameter unit are also read. When the pre-sealing zone pressure control is in a strictly corrected state, if the corrected transition position does not fall into the prohibited pressure abrupt change range, and the corrected transition width is not greater than the product of the original transition width and the ratio of the strictly corrected width, then the candidate flow channel parameter unit is determined to meet the differential pressure control requirements. When the pre-sealing zone pressure control is in a general corrected state, if the corrected transition position does not fall into the prohibited pressure abrupt change range, and the corrected transition width is not greater than the product of the original transition width and the general corrected width, then the candidate flow channel parameter unit is determined to meet the differential pressure control requirements; otherwise, it is discarded.

[0319] The strict correction width ratio and the general correction width ratio are determined based on the allowable transition width correction range under the strict correction state and the general correction state, respectively.

[0320] Next, scouring control screening is performed. The upper limit of the wall-attached velocity, the impact avoidance direction, and the sequential change order are read from the scouring control data. The original and corrected change rhythms corresponding to each candidate flow channel parameter unit are also read. First, the original change rhythms in the pressure transmission correction field corresponding to all candidate flow channel parameter units in the first candidate flow channel parameter set are statistically analyzed, and the arithmetic mean of all original change rhythms is calculated. This arithmetic mean is determined as the set's baseline change rhythm. Then, the angle between the corrected section change direction and the impact avoidance direction is calculated, and this angle is determined as the change correction deviation angle. Finally, it is checked whether the corrected change rhythm meets the change rhythm constraints.

[0321] When the velocity constraint in the pressure transmission zone is in a strict state, if the incremental correction deviation angle is not greater than the incremental direction deviation threshold, and the correction incremental rhythm is not greater than the product of the set reference incremental rhythm and the strict rhythm screening ratio, then the candidate flow channel parameter unit is determined to meet the scouring control requirements; otherwise, it is rejected.

[0322] The threshold for the changing direction deviation is determined based on the maximum allowable directional deviation when the pressure transmission zone meets the impact avoidance requirements; the strict rhythm screening ratio and the general rhythm screening ratio are determined based on the upper limit ratio of the changing rhythm that can be retained under strict flow velocity constraint state and general flow velocity constraint state, respectively.

[0323] According to the processing results of the scour control screening based on the progressive correction deviation angle and the correction progressive rhythm in S54, the scour control data extraction stage and the contact control screening stage maintain the same judgment criteria in terms of impact avoidance direction, progressive direction deviation threshold, wall-attached flow velocity upper limit and progressive rhythm constraint.

[0324] Perform a second round of venting control screening. Read the backflow retention avoidance zone, end-out direction, and opening / dispersion sequence from the venting control data; calculate the angle between the corrected outlet exit direction and the end-out direction, and determine this angle as the exit correction deviation angle; if the corrected end-out position does not fall within the backflow retention avoidance zone, and the exit correction deviation angle is not greater than the exit direction deviation threshold, determine that the candidate flow channel parameter unit meets the venting control requirements; otherwise, discard it.

[0325] The outgoing direction deviation threshold is determined based on the maximum allowable direction deviation when the unloading zone meets the end-out requirements.

[0326] Finally, only the candidate flow channel parameter units that simultaneously meet the requirements of differential pressure control, flushing control, and venting control are retained, and these candidate flow channel parameter units are written into the second candidate flow channel parameter set table to obtain the second candidate flow channel parameter set.

[0327] S55, based on the target operating condition data, performs operating condition adaptation screening on the second candidate flow channel parameter set to obtain the third candidate flow channel parameter set.

[0328] Specifically, the target flow rate, target head, target conveying medium type, conveying medium design density, conveying medium design kinematic viscosity, solid volume fraction, allowable value of mechanical seal leakage, and allowable value of whole machine vibration amplitude are read from the target operating condition data. The pre-sealing correction field, pressure transmission correction field, and unloading correction field corresponding to each candidate flow channel parameter unit are read from the second candidate flow channel parameter set. The end-derived direction in the exhaust control data is read from the contact control data.

[0329] First, calculate the local flow channel rhythm coefficient and the unloading zone adaptation coefficient. The local flow channel rhythm coefficient is the ratio of the corrected transition width to the corrected gradient rhythm. The unloading zone adaptation coefficient is the cosine of the angle between the corrected outlet direction and the end outlet direction multiplied by the position proximity coefficient; the position proximity coefficient is 1 minus the ratio of the end diverging outlet distance to the outlet reference distance; the outlet reference distance is the maximum value of all end diverging outlet distances in the second candidate flow channel parameter set; when the maximum value is not greater than the preset distance invalid threshold, the outlet reference distance is taken as the preset minimum reference distance.

[0330] The preset distance invalid threshold is used to identify whether the exit reference distance has lost its distinguishing function, and the preset minimum reference distance is used to maintain the position proximity coefficient when the end-opening exit distance is too small.

[0331] After using the proximity coefficient between the end-of-line divergence outlet and the participating position, the working condition adaptation screening can directly evaluate whether the outlet end is close to the outlet release boundary.

[0332] The flow rate operating level is determined based on the target flow rate, and the head operating level is determined based on the target head. When the target flow rate is not greater than the median flow rate threshold, it is determined to be a low-to-medium flow rate operating condition; when the target flow rate is greater than the median flow rate threshold, it is determined to be a medium-to-high flow rate operating condition. The median flow rate threshold is preferably taken as the median of the corresponding flow rates of all operating point records in the project selection list; when the project selection list only records a single target flow rate, that target flow rate is taken as the median flow rate threshold.

[0333] When the target head is not less than the median head threshold, it is determined to be a medium-high head operating condition; when the target head is less than the median head threshold, it is determined to be a medium-low head operating condition. The median head threshold is preferentially taken as the median of the head values ​​corresponding to all operating condition records in the project selection sheet; when the project selection sheet only records a single target head, that target head is taken as the median head threshold. After classifying flow rate and head levels based on the median value, multiple operating condition records can be compressed into combinations of operating condition levels.

[0334] Establish the correspondence between operating condition level combinations and adaptation boundaries. Prototype operating condition tests should preferentially use the target conveying medium body corresponding to the target operating condition data; when the target conveying medium body cannot be directly used, an equivalent test medium that meets the aforementioned equivalent medium matching conditions should be used. For candidate flow channel parameter units screened through contact control, prototype operating condition tests should be performed under all operating condition level combinations. Under each operating condition level combination, candidate flow channel parameter units that simultaneously meet all of the following conditions are statistically analyzed: the mechanical seal leakage does not exceed the allowable value of mechanical seal leakage, which is calculated by dividing the total volume of leakage medium collected within a preset leakage statistics window by the statistics duration; the overall machine vibration amplitude does not exceed the allowable value of overall machine vibration amplitude, which is obtained by continuously sampling within a preset vibration sampling window using vibration sensors arranged at the pump body bearing housing position, and taking the maximum vibration displacement peak value within the sampling window; the outlet flow direction is continuously stable, which means that when sampling is performed according to a preset flow sampling cycle, the angle between the average outlet flow direction and the end outlet direction within a number of consecutive preset flow judgment cycles is not greater than the flow stability angle threshold; the test efficiency is not lower than the product of the average efficiency of similar candidate flow channel parameter units and the efficiency maintenance ratio threshold.

[0335] The preset leakage statistics window, preset vibration sampling window, preset flow diversion sampling cycle, preset flow diversion judgment cycle number, flow diversion stability angle threshold, and efficiency maintenance ratio threshold are preset according to the leakage statistics stability, vibration amplitude discrimination stability, flow diversion direction continuity judgment requirements, and efficiency maintenance requirements, respectively.

[0336] The average efficiency of similar candidate flow channel parameter units refers to the arithmetic mean of the test efficiencies of all candidate flow channel parameter units that passed the contact control screening in the same round of prototype testing under the same operating condition level combination. By using the average efficiency in the same round of testing as the comparison benchmark, the efficiency judgment is no longer affected by the drift of cross-batch test conditions; by limiting the average efficiency of similar candidate flow channel parameter units to the same operating condition boundary and the same test batch, the efficiency comparison benchmark can avoid the evaluation drift caused by cross-operating condition and cross-batch comparisons.

[0337] For candidate flow channel parameter units that meet all the above conditions, the maximum value of their local flow channel rhythm coefficient and the minimum value of their derived adaptation coefficient in the unloading zone are calculated respectively. The maximum value of the local flow channel rhythm coefficient is determined as the rhythm stability boundary under the combination of operating conditions, and the minimum value of the derived adaptation coefficient in the unloading zone is determined as the derived stability boundary under the combination of operating conditions.

[0338] When complete boundary statistical results are not formed during prototype operating condition testing, a preset operating condition adaptation threshold set is used as the operating condition adaptation boundary. This preset operating condition adaptation threshold set is the median value of the statistical results from the verified representative centrifugal pump prototype operating condition tests under all operating condition level combinations, and is pre-stored. The preset operating condition adaptation threshold set includes at least the upper limit of stability of the local flow channel rhythm coefficient and the lower limit of stability of the derived adaptation coefficient of the unloading zone corresponding to each operating condition level combination. By using the statistical median value rather than extreme values ​​to form the preset operating condition adaptation threshold set, it better reflects the median stable boundary of the verified prototype. Even if complete boundary statistical results are not formed during the current prototype operating condition test, the local flow channel rhythm coefficient and the derived adaptation coefficient of the unloading zone can still be filtered around the verified median stable boundary, ensuring that the operating condition adaptation boundary remains continuous and consistent even when complete test data for the current test is lacking.

[0339] After determining the current flow rate and head operating conditions, the parameters are filtered according to the upper limit of the local flow channel rhythm coefficient and the lower limit of the offflow zone derived adaptation coefficient corresponding to the current operating condition combination. Only candidate flow channel parameter units whose local flow channel rhythm coefficient is not greater than the upper limit of the local flow channel rhythm coefficient corresponding to the current operating condition combination, and whose offflow zone derived adaptation coefficient is not less than the lower limit of the offflow zone derived adaptation coefficient corresponding to the current operating condition combination, are retained. Finally, the candidate flow channel parameter units that pass the operating condition adaptation screening are written into the third candidate flow channel parameter set table to obtain the third candidate flow channel parameter set.

[0340] S56, determine the candidate flow channel parameters in the third candidate flow channel parameter set as the target flow channel parameters.

[0341] Specifically, when the third candidate flow channel parameter set contains only a single candidate flow channel parameter unit, that candidate flow channel parameter unit is directly determined as the target flow channel parameter.

[0342] When the third candidate flow channel parameter set contains multiple candidate flow channel parameter units, first compare the local flow channel rhythm coefficients of each candidate flow channel parameter unit, and select the candidate flow channel parameter unit with the smallest local flow channel rhythm coefficient as the priority candidate flow channel parameter unit; when multiple candidate flow channel parameter units have the same minimum local flow channel rhythm coefficient, then compare the outflow area derived adaptation coefficients of each candidate flow channel parameter unit, and select the candidate flow channel parameter unit with the largest outflow area derived adaptation coefficient as the current priority candidate flow channel parameter unit; when both the local flow channel rhythm coefficient and the outflow area derived adaptation coefficient are the same, then compare... The candidate flow channel parameter unit with the smallest end-opening outlet distance is selected as the current priority candidate flow channel parameter unit. When the above comparison results are still the same, the absolute value of the difference between the global path coordinates corresponding to the pre-sealing correction field and the global path coordinates corresponding to the pressure transmission correction field, and the absolute value of the difference between the global path coordinates corresponding to the pressure transmission correction field and the global path coordinates corresponding to the unloading correction field are calculated respectively. The absolute values ​​are then added together to obtain the path connection difference sum. The candidate flow channel parameter unit with the smallest path connection difference sum is selected as the target flow channel parameter.

[0343] The above sorting rules revolve around the compactness of local flow channel rhythm, the adaptability of outlet discharge, the proximity of the end outlet, and the continuity of regional path connection. This ensures that the final target flow channel parameters not only meet the local constraints of the pre-sealing zone, pressure transmission zone, and unloading zone, but also prioritize the combination of a more compact overall flow channel sequence and smoother outlet release under the three-stage linkage.

[0344] After the target flow channel parameters are determined, they are written into the target flow channel parameter field, and a target flow channel parameter record table is established. The target flow channel parameter record table includes at least the pre-sealing zone target correction field, the pressure transmission zone target correction field, the unloading zone target correction field, and the target scheme identifier field. When the third candidate flow channel parameter set is empty, no target flow channel parameters are written; only the sequence correction verification mark and the corresponding reason are recorded.

[0345] Example 2:

[0346] Please see Figure 2 As shown, this embodiment discloses a centrifugal pump volute flow channel parameter optimization system, including:

[0347] The data acquisition module is used to collect data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions.

[0348] The inner wall partition identification module identifies the partitions of the inner wall of the volute based on the volute structure data and mechanical seal installation data, thus obtaining the pre-sealing zone, pressure transmission zone and unloading zone.

[0349] The contact control analysis module performs contact control analysis based on the contact requirement data of the pre-sealing zone, pressure transmission zone, unloading zone, and mechanical seal, as well as the target operating condition data, to obtain contact control data.

[0350] The flow channel adjustment item extraction module extracts flow channel adjustment items based on pre-sealing zone, pressure transmission zone, unloading zone, contact control data and volute structure data to obtain regional adjustment data;

[0351] The flow channel sequence correction module corrects the flow channel sequence based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data to obtain target flow channel parameters.

[0352] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0353] Finally: The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for optimizing the flow channel parameters of a centrifugal pump volute, characterized in that, include: Collect data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions. Based on the volute structure data and mechanical seal installation data, the inner wall of the volute is divided into zones to obtain the pre-sealing zone, pressure transmission zone and unloading zone. Based on the contact requirement data of the pre-sealing zone, pressure transmission zone, unloading zone, and mechanical seal, as well as the target operating condition data, contact control analysis is performed to obtain contact control data. Based on the pre-sealing zone, pressure transmission zone, unloading zone, contact control data, and volute structure data, flow channel adjustment items are extracted to obtain regional adjustment data; Based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data, the flow channel sequence is corrected to obtain the target flow channel parameters.

2. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 1, characterized in that, Methods for obtaining the pre-sealing zone, pressure transmission zone, and unloading zone include: Extract the inner wall contour data and the outlet position data of the volute from the volute structure data, and extract the inner wall contour of the volute from the inner wall contour data. Extract the mechanical seal retaining ring position data from the mechanical seal installation data; Based on the position data of the mechanical seal retaining ring, the inner wall segment of the volute with the smallest distance from the mechanical seal retaining ring is determined in the inner wall profile of the volute, thus obtaining the starting region; Based on the volute outlet location data, the volute inner wall segment directly connected to the volute outlet is determined in the volute inner wall contour to obtain the end region. Along the contour of the inner wall of the volute from the starting region to the ending region, the inner wall of the volute between the starting region and the ending region is divided into continuous regions to obtain the intermediate continuous region. The initial region is defined as the pre-sealing region, the intermediate continuous region is defined as the pressure transmission region, and the final region is defined as the unloading region.

3. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 1, characterized in that, Methods for obtaining contact control data include: Based on the pre-sealing zone, mechanical seal contact requirement data, and target operating condition data, differential pressure control data is obtained; Based on the pressure transmission zone, mechanical seal contact requirement data, and target operating condition data, scour control data is obtained; Based on the data on the unloading zone, mechanical seal contact requirements, and target operating conditions, exhaust control data is obtained; Based on the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the differential pressure control data, scouring control data, and discharge control data are integrated with regional constraints to obtain contact control data.

4. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 3, characterized in that, Methods for obtaining differential pressure control data include: Extract the mechanical seal compression range and total clamping force range from the mechanical seal contact requirement data; Based on the mechanical seal compression range and the impeller outlet position and direction data in the impeller outlet structure data, determine the pressure change direction in the pre-sealing zone from the impeller outlet to the pressure transmission zone. Based on the total clamping force range and the target head in the target working condition data, determine the allowable pressure variation range of the pre-sealing area; Based on the distribution of the turning points of the inner wall of the volute in the pre-sealing area in the volute structure data, the pressure change prohibition zone in the pre-sealing area is determined. By correlating the pressure change direction, the allowable pressure change range, and the prohibited pressure change range within the same region, differential pressure control data is obtained.

5. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 3, characterized in that, Methods for obtaining flushing control data include: Extract the end face specific pressure range from the mechanical seal contact requirement data; Based on the specific pressure range at the end face, determine the upper limit of the wall-attached flow velocity in the pressure transmission zone; Based on the target flow rate in the target operating condition data and the extension direction of the inner wall of the volute located in the pressure transmission zone in the volute structure data, the impact avoidance direction of the pressure transmission zone is determined. Based on the arrangement order of the volute inner wall cross sections in the pressure transmission zone in the volute structure data, the progressive continuity order of the pressure transmission zone is determined. The flow velocity constraints of the upper limit of the wall-attached flow velocity, the impact avoidance direction, and the progressive sequence are checked to obtain scour control data.

6. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 3, characterized in that, Methods for obtaining exhaust control data include: Extract the total clamping force range and end face specific pressure range from the mechanical seal contact requirement data; Based on the total clamping force range and the end face specific pressure range, determine the backflow retention and avoidance zone of the unloading area; Based on the target flow rate in the target operating condition data and the volute outlet position data in the volute structure data, determine the end discharge direction of the unloading zone; Based on the extension sequence of the end profile of the inner wall of the volute located in the unloading zone in the volute structure data, the opening and closing continuity sequence of the unloading zone is determined. The backflow retention and avoidance interval, the end outlet direction, and the opening and dispersing sequence are checked to obtain the discharge control data.

7. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 1, characterized in that, Methods for obtaining regional adjustment data include: Pre-sealing adjustment data is obtained based on pre-sealing zone, differential pressure control data, and volute structure data; Based on the pressure transmission zone, scour control data, and volute structure data, pressure transmission adjustment data is obtained; Based on the unloading zone, exhaust control data, and volute structure data, unloading adjustment data is obtained; According to the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data are partitioned and connected to obtain regional adjustment data.

8. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 7, characterized in that, Methods for obtaining pre-sealing adjustment data include: Based on the pressure change direction, allowable pressure change range, and prohibited pressure change range in the differential pressure control data, multiple volute transition sections in the pre-sealing zone are screened: Identify the volute transition section located outside the pressure change forbidden zone and whose arrangement direction is consistent with the pressure change direction, and obtain the target volute transition section. Extract the transition width and turning point corresponding to the transition part of the target volute; Based on the allowable pressure variation range, the transition width and turning point are constrained and matched to obtain pre-sealing adjustment data.

9. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 7, characterized in that, Methods for obtaining pressure adjustment data include: Based on the upper limit of the wall-attached flow velocity, the impact avoidance direction, and the sequential change in the scour control data, multiple volute cross-sectional change points in the pressure transmission zone are screened: Identify the volute cross-section gradient locations that conform to the impact avoidance direction and satisfy the continuous gradient sequence, and obtain the target volute cross-section gradient locations. Extract the cross-sectional gradient direction and gradient rhythm corresponding to the gradient parts of the target volute cross-section; Based on the continuous sequence of changes, the direction and rhythm of cross-sectional changes are continuously matched to obtain pressure transmission adjustment data.

10. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 7, characterized in that, Methods for obtaining offflow adjustment data include: Based on the backflow retention avoidance zone, end outlet direction, and opening / dispersion continuity sequence in the discharge control data, multiple volute outlet locations in the unloading zone are screened: Determine the volute exit point that is located outside the backflow retention avoidance zone and conforms to the end exit direction and opening and closing continuous sequence, and obtain the target volute exit point; Extract the outlet direction and end divergence position corresponding to the outlet part of the target volute; Based on the continuous sequence of opening and dispersing, the outlet discharge direction and the terminal opening and dispersing position are matched to obtain the unloading adjustment data.

11. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 1, characterized in that, Methods for obtaining target flow channel parameters include: Based on regional adjustment data and contact control data, the flow channel sequence is corrected to obtain a set of candidate flow channel parameters. Based on the impeller outlet structure data and volute structure data, the candidate flow channel parameter set is filtered for transition continuity to obtain the first candidate flow channel parameter set; Based on the contact control data, the first candidate flow channel parameter set is screened by contact control to obtain the second candidate flow channel parameter set; Based on the target operating condition data, the second candidate flow channel parameter set is screened for operating condition adaptation to obtain the third candidate flow channel parameter set; The candidate flow channel parameters in the third set of candidate flow channel parameters are determined as the target flow channel parameters.

12. The method for optimizing the flow channel parameters of a centrifugal pump volute according to claim 11, characterized in that, Methods for obtaining the candidate flow channel parameter set include: Extract pre-sealing adjustment data, pressure transmission adjustment data, and unloading adjustment data from the regional adjustment data; Extract differential pressure control data, flushing control data, and venting control data from the contact control data; Based on the differential pressure control data, the transition width and turning point in the pre-sealing adjustment data are corrected to obtain the pre-sealing correction data; Based on the scouring control data, the cross-sectional change direction and change rhythm in the pressure transmission adjustment data are corrected to obtain pressure transmission correction data; Based on the discharge control data, the outlet discharge direction and the end opening position in the discharge adjustment data are corrected to obtain the discharge correction data; Following the spatial order of the pre-sealing zone, pressure transmission zone, and unloading zone, the pre-sealing correction data, pressure transmission correction data, and unloading correction data are connected and arranged in the flow channel segment to obtain a set of candidate flow channel parameters.

13. A centrifugal pump volute flow channel parameter optimization system, used to implement the centrifugal pump volute flow channel parameter optimization method according to any one of claims 1-12, characterized in that, include: The data acquisition module is used to collect data on the volute structure, impeller outlet structure, mechanical seal installation, mechanical seal contact requirements, and target operating conditions. The inner wall partition identification module identifies the partitions of the inner wall of the volute based on the volute structure data and mechanical seal installation data, thus obtaining the pre-sealing zone, pressure transmission zone, and unloading zone. The contact control analysis module performs contact control analysis based on the contact requirement data of the pre-sealing zone, pressure transmission zone, unloading zone, and mechanical seal, as well as the target operating condition data, to obtain contact control data. The flow channel adjustment item extraction module extracts flow channel adjustment items based on pre-sealing zone, pressure transmission zone, unloading zone, contact control data and volute structure data to obtain regional adjustment data; The flow channel sequence correction module corrects the flow channel sequence based on regional adjustment data, impeller outlet structure data, contact control data, and target operating condition data to obtain the target flow channel parameters.

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