A high-performance hydraulic model design method

Abstract

The present invention belongs to the technical field of vane pump hydraulic model design, and specifically relates to a high-performance hydraulic model design method. The specific technical solution is as follows: designing a vane pump hydraulic model based on pump design parameters, calculating the external characteristics and internal flow field of the hydraulic model, obtaining the matching relationship between the impeller and the pressure chamber's high-efficiency point and the design point, and the internal flow field distribution; qualitatively judging the matching of the impeller and the pressure chamber, and determining the adjustment direction of the hydraulic model adjustment parameters; combining the calculation results of the hydraulic model's internal flow field, fine-tuning the hydraulic model's geometric dimensions to obtain an optimized vane pump hydraulic model. The purpose of optimizing the design of a high-performance hydraulic model is achieved by combining unified macro-matching judgment guidance with flow field information feedback fine-tuning guidance.

Description

Technical Field

[0001] The invention belongs to the technical field of vane pump hydraulic model design, and particularly relates to a high-performance hydraulic model design method. Background Art

[0002] Vane pumps are widely used and in large quantities. Their performance plays a decisive role in operational quality and energy conservation and emission reduction. Designing a high-performance hydraulic model that meets these requirements has long been a key concern for vane pump designers. Due to the complexity of their structure and internal flow, effective and feasible optimization design methods are a key focus for researchers and engineers.

[0003] Many researchers have conducted extensive research on the optimization design of performance hydraulic models. Among the existing technologies, the patented technology with application number CN201810163423.3 proposes a design method that combines discrete sample statistics with a robustness measurement function. This method can obtain the optimal solution within the boundary conditions and achieve the purpose of optimizing the design of mixed flow pumps. The patented technology with application number CN201910179624.7 proposes a multi-condition optimization design method for the spatial guide vanes of mixed flow pumps. By selecting three geometric parameters, namely the spatial guide vane inlet placement angle, the guide vane diffusion angle, and the guide vane blade wrap angle, as optimization variables, the weighted average maximum efficiency of the mixed flow pump under different impeller blade placement angles is used as the optimization target, and a weight factor is used to establish an optimization mathematical model. The genetic algorithm is combined with the functional relationship to optimize the hydraulic model.

[0004] The above method mainly optimizes the hydraulic model's performance by focusing on its external characteristics, but does not consider the control of adverse flow phenomena in the internal flow field or the hydraulic matching between the impeller and the pressure chamber. Based on this, the present invention proposes a high-performance hydraulic model design method. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a high-performance hydraulic model design method.

[0006] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a high-performance hydraulic model design method, which designs a vane pump hydraulic model according to the pump design parameters, calculates the external characteristics and internal flow field of the hydraulic model, obtains the matching relationship between the impeller and the water pressure chamber high-efficiency point and the design point and the internal flow field distribution; qualitatively judges the matching of the impeller and the water pressure chamber, and determines the adjustment direction of the hydraulic model adjustment parameters; combines the hydraulic model flow field calculation results, fine-tunes the hydraulic model geometric dimensions, and obtains an optimized vane pump hydraulic model.

[0007] Preferably, the matching of the impeller and the pressure chamber is qualitatively judged, and the adjustment direction of the hydraulic model adjustment parameters is:

[0008] According to the efficiency curve and head loss curve of the impeller and pressurized water chamber, determine the adjustment direction of the hydraulic model according to the position of the high-efficiency point and the size of the head loss, so that the high-efficiency point of the impeller and pressurized water chamber is close to the design point and the loss head of the impeller and pressurized water chamber is small;

[0009] If the flow rate Q1 corresponding to the high efficiency point of impeller conversion efficiency is less than the design flow rate Q d , then adjust the parameter towards a direction higher than the flow rate Q1; otherwise, adjust it towards a direction lower than the flow rate Q1;

[0010] If the flow rate Q2 corresponding to the high efficiency point of the guide vane conversion efficiency is less than the design flow rate Q d , then the adjustment parameter is adjusted towards a direction higher than the flow rate Q2; otherwise, it is adjusted towards a direction lower than the flow rate Q2.

[0011] Preferably, the blade geometric parameters are adjusted according to the relationship between the liquid flow angle of the internal flow field and the inlet and outlet placement angles of the impeller and guide vanes.

[0012] Preferably, the geometric dimensions of the hydraulic model include inlet and outlet diameters, impeller outlet width, blade inlet and outlet angles, and blade wrap angle.

[0013] Preferably, the matching of the impeller and the pressure chamber is qualitatively judged to determine the adjustment direction of the hydraulic model adjustment parameters: the geometric size parameters with high sensitivity are adjusted according to the adjustment direction, including the impeller outlet width.

[0014] Preferably, the geometric dimensions of the hydraulic model are fine-tuned: geometric dimension parameters with low sensitivity are adjusted, including blade wrap angle and inlet placement angle.

[0015] Preferably, the impeller conversion efficiency is calculated as follows:

[0016]

[0017] Among them, η imp is the impeller efficiency; p imp-out is the total pressure at the impeller outlet; p in is the total pressure at the inlet of the hydraulic model; Q is the actual flow rate out of the hydraulic model; P is the input impeller power;

[0018] The guide vane conversion efficiency is calculated as follows:

[0019]

[0020] Among them, η dif is the efficiency of the water chamber; p dif-out is the total pressure at the outlet of the pressure chamber.

[0021] Preferably, the loss head calculation method is as follows:

[0022]

[0023]

[0024] Where ΔH imp is the impeller loss head; ΔH dif is the loss head of the water chamber; ρ is the medium density; g is the acceleration of gravity.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The method of the present invention combines internal flow field characteristics with the matching of external characteristics. By using the control of poor internal flow phenomena and the multi-dimensional optimization of the hydraulic matching between the impeller and the pressure chamber, the internal flow field and external characteristics are combined to form a comprehensive characterization method for hydraulic model performance, which can be used to judge the performance of the hydraulic model. By providing feedback on the results of internal flow information, poor flow is controlled. Simultaneously, by judging the matching of the impeller and the pressure chamber, the optimal efficiency point of each hydraulic component is adjusted to achieve optimal matching optimization of each hydraulic component, ultimately achieving the optimized design of a high-performance hydraulic model.

[0027] 1. The impeller and pressure chamber matching judgment method is used to determine the specific adjustment direction of the hydraulic model impeller and pressure chamber to achieve the purpose of unified and synchronous matching of the two, and ultimately achieve the purpose of optimizing the hydraulic model.

[0028] 2. Use the internal flow field feedback method to provide detailed guidance on fine-tuning the geometric parameters of the hydraulic model.

[0029] 3. Optimal design of high-performance hydraulic models is achieved through local fine-tuning of hydraulic model matching and flow field information feedback.

[0030] 4. The goal of optimizing the design of high-performance hydraulic models is achieved by adopting a combination of unified judgment guidance based on macro-matching and fine-tuning guidance based on flow field information feedback. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of the design method of the present invention;

[0032] Figure 2 This is the hydraulic model efficiency matching judgment curve of the present invention;

[0033] Figure 3 This is the head loss matching judgment curve of the hydraulic model of the present invention;

[0034] Figure 4 This is a diagram showing the relationship between the liquid flow in the impeller and the geometric matching of the blades of the present invention;

[0035] Figure 5 Schematic diagram of the poor flow condition in the water pressure chamber of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0037] like Figure 1-5 As shown, the present invention discloses a high-performance hydraulic model design method, the core idea of ​​which is to design a vane pump hydraulic model based on the pump design parameters, calculate the external characteristics and internal flow field of the hydraulic model through the fluid dynamics method (CFD), and obtain the matching relationship between the high-efficiency point and the design point of the impeller and the water chamber, as well as the distribution of the internal flow field. The hydraulic model optimization adopts the method of statistically analyzing the conversion efficiency and head loss of the impeller and the guide vane respectively, evaluating the hydraulic performance of the impeller and the guide vane separately, and optimizing the geometric parameters of the hydraulic model respectively; at the same time, statistically comparing the performance of small flow, design flow and large flow, qualitatively judging the matching of the impeller and the water chamber, and determining the adjustment direction of the main parameters of the hydraulic model; combining the CFD hydraulic model flow field calculation results, fine-tuning the geometric dimensions of the hydraulic model to obtain an optimized vane pump hydraulic model.

[0038] It should be noted that the above-mentioned small flow refers to the flow less than the design working condition Q d The situation is that the flow rate Q1 corresponding to the impeller high efficiency point is less than the design flow rate Q d The flow rate Q2 corresponding to the high efficiency point of the guide vane is less than the design flow rate Q d The above large flow rate means that the flow rate Q1 corresponding to the impeller high efficiency point is greater than the design flow rate Q d The flow rate, the flow rate Q2 corresponding to the high efficiency point of the guide vane is greater than the design flow rate Q d The high efficiency point is the point with the highest conversion efficiency. The impeller-pressurized chamber matching is determined based on the impeller-pressurized chamber efficiency and head loss.

[0039] Furthermore, the pump design parameters include the design flow rate Q d , design head H and design speed n.

[0040] Furthermore, the geometric dimensions of the hydraulic model include inlet and outlet diameters, impeller outlet width, blade inlet and outlet angles, blade wrap angle, front and rear cover curves of the impeller and guide vane axial projections, blade placement angle rules, and volute throat area.

[0041] Furthermore, the matching of the impeller and the pressure chamber is qualitatively judged, and the adjustment direction of the hydraulic model adjustment parameters is: according to the efficiency curve and head loss curve of the impeller and the pressure chamber, such as Figure 2 and 3As shown, the hydraulic model is adjusted based on the location of the high-efficiency point and the amount of head loss, ensuring that the high-efficiency points of the impeller and pressurized water chamber are close to the design point while minimizing the loss head of the impeller and pressurized water chamber. Specifically, by adjusting relevant parameters, the flow path is made more consistent with the flow pattern, essentially improving the compatibility between the flow path and the liquid flow. The principle for determining loss head is that the minimum loss value is generally found near the design point, which is considered optimal.

[0042] If the flow rate Q1 corresponding to the high efficiency point of impeller conversion efficiency is less than the design flow rate Q d , then adjust the parameter towards a direction higher than the flow rate Q1; otherwise, adjust it towards a direction lower than the flow rate Q1;

[0043] If the flow rate Q2 corresponding to the high efficiency point of the guide vane conversion efficiency is less than the design flow rate Q d , then the adjustment parameter is adjusted towards a direction higher than the flow rate Q2; otherwise, it is adjusted towards a direction lower than the flow rate Q2.

[0044] Furthermore, the compatibility between the impeller and the pressurized water chamber is qualitatively determined to determine the direction of adjustment for the hydraulic model parameters. Based on this adjustment direction, the most sensitive geometric parameters are adjusted, including the impeller outlet width, the impeller and guide vane wrap angles, and the volute throat area. The term "most sensitive" here refers to geometric parameters that are highly sensitive to flow rate.

[0045] Furthermore, the hydraulic model's geometry was fine-tuned based on the CFD hydraulic model's flow field calculation results. The blade geometry parameters were adjusted based on the relationship between the internal flow field's liquid flow angle and the impeller and guide vane inlet and outlet angles. These geometric parameters included the impeller inlet angle, blade wrap angle, and front and rear cover plate curves. The difference between the liquid flow angle and the blade angle is the angle of attack, and the goal here was to improve the matching between the liquid flow angle and the blade angle.

[0046] Furthermore, fine-tune the hydraulic model geometry: adjust less sensitive geometric parameters, including blade wrap angle and inlet placement angle. Here, less sensitive refers to geometric parameters that are less sensitive to flow rate.

[0047] Furthermore, the efficiency of the impeller is the ratio of the effective work done by the impeller to the input shaft power, that is, the impeller conversion efficiency. The impeller conversion efficiency is calculated as follows:

[0048]

[0049] Among them, η imp is the impeller efficiency, %; p imp-out is the total pressure at the impeller outlet, Pa; p in is the total pressure at the inlet of the hydraulic model, Pa; Q is the actual flow rate out of the hydraulic model, kg / s; P is the input impeller power, W;

[0050] The efficiency of the guide vane is the ratio of the effective work done at the guide vane outlet to the effective work done by the impeller, that is, the guide vane conversion efficiency. The guide vane conversion efficiency is calculated as follows:

[0051]

[0052] Among them, η dif is the efficiency of the water chamber, %; p dif-out is the total pressure at the outlet of the pressure chamber, Pa.

[0053] Furthermore, the head loss of the impeller is the potential energy representation of the difference between the effective input energy and the impeller output energy; the head loss of the pressure chamber is the potential energy representation of the difference between the guide vane outlet energy and the inlet energy. The calculation method of the loss head is as follows:

[0054]

[0055]

[0056] Where ΔH imp is the impeller loss head, m; ΔH dif is the loss head of the water chamber, m; ρ is the medium density, kg / m 3 ; g is the acceleration due to gravity, m / s 2 .

[0057] Example

[0058] like Figure 1 As shown in the flowchart, the design parameter Q is given d , H, n, based on the preliminary design of the vane pump hydraulic model and CFD calculation, obtain Figure 1 The efficiency and head loss matching judgment curve is used to guide the model optimization direction.

[0059] like Figure 2-3 As shown, first determine the optimization direction of the impeller and guide vane according to the efficiency distribution of the impeller. The specific operation is as follows: If the flow rate at the impeller's highest efficiency point P1 is less than 1.0Q d , then the impeller parameters are adjusted towards the direction of large flow, otherwise they are adjusted towards the direction of small flow; the optimization adjustment method of the guide vane is the same as that of the impeller. Secondly, according to the distribution of the impeller head loss, the minimum head loss position and the design flow rate 1.0Q are determined. d The relationship between the minimum head loss is optimized and adjusted to the design working condition 1.0Q d Nearby, so that the optimal operating condition is close to the design operating condition; the optimization adjustment of the guide vane is consistent with the impeller.

[0060] like Figure 4-5The figure shows the relationship between the flow and blades within the impeller and the poor flow within the pressurized water chamber. This shows a mismatch between the impeller inlet flow angle and the blade placement angle, and poor flow within the guide vanes. By combining this internal flow field information, the geometric parameters of the hydraulic model were fine-tuned to improve its performance.

[0061] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various deformations, modifications, and substitutions made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A high-performance hydraulic model design method, characterized by: Design a hydraulic model for the vane pump based on the pump design parameters, calculate the external characteristics and internal flow field of the hydraulic model, and obtain the matching relationship between the high-efficiency point and the design point of the impeller and the pressure chamber, as well as the distribution of the internal flow field; qualitatively determine the matching of the impeller and the pressure chamber, and determine the adjustment direction of the hydraulic model adjustment parameters; Qualitatively judge the matching between the impeller and the pressurized water chamber, and adjust the parameters of the hydraulic model: According to the efficiency curve and head loss curve of the impeller and pressurized water chamber, determine the adjustment direction of the hydraulic model according to the position of the high-efficiency point and the size of the head loss, so that the high-efficiency point of the impeller and pressurized water chamber is close to the design point and the loss head of the impeller and pressurized water chamber is small; The calculation method of lost head is as follows: Where ΔH imp is the impeller loss head; ΔH dif is the loss head of the water chamber; ρ is the medium density; g is the acceleration of gravity; The impeller conversion efficiency is calculated as follows: Among them, η imp is the impeller efficiency; p imp-out is the total pressure at the impeller outlet; p in is the total pressure at the inlet of the hydraulic model; Q is the actual flow rate out of the hydraulic model; P is the input impeller power; The guide vane conversion efficiency is calculated as follows: Among them, η dif is the efficiency of the water chamber; p dif-out is the total pressure at the outlet of the pressure chamber; If the flow rate Q1 corresponding to the high efficiency point of impeller conversion efficiency is less than the design flow rate Q d , then adjust the parameter towards a direction higher than the flow rate Q1; otherwise, adjust it towards a direction lower than the flow rate Q1; If the flow rate Q2 corresponding to the high efficiency point of the guide vane conversion efficiency is less than the design flow rate Q d , then adjust the parameter towards a direction higher than the flow rate Q2; otherwise, adjust it towards a direction lower than the flow rate Q2; Combined with the calculation results of the internal flow field of the hydraulic model, the geometric dimensions of the hydraulic model are fine-tuned to obtain the optimized vane pump hydraulic model.

2. A high-performance hydraulic model design method according to claim 1, characterized in that: Combined with the calculation results of the internal flow field of the hydraulic model, the geometric dimensions of the hydraulic model are fine-tuned: the blade geometric parameters are adjusted according to the relationship between the liquid flow angle of the internal flow field and the inlet and outlet placement angles of the impeller and guide vane.

3. A high-performance hydraulic model design method according to claim 2, characterized in that: The geometric dimensions of the hydraulic model include inlet and outlet diameters, impeller outlet width, blade inlet and outlet angles, and blade wrap angle.

4. A high-performance hydraulic model design method according to claim 3, characterized in that: Qualitatively judge the matching between the impeller and the pressurized water chamber, and determine the adjustment direction of the hydraulic model adjustment parameters: adjust the geometric size parameters with high sensitivity according to the adjustment direction, including the impeller outlet width.

5. A high-performance hydraulic model design method according to claim 4, characterized in that: Fine-tune the geometric dimensions of the hydraulic model: adjust the geometric parameters with low sensitivity, including blade wrap angle and inlet placement angle.

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