Method, device and equipment for evaluating hydraulic work performance of impulse water turbine and storage medium

Abstract

The application provides a method, device and equipment for evaluating the hydraulic work performance of an impulse water turbine and a storage medium. After the surface of a water bucket of the impulse water turbine is rasterized, for each grid area on the surface of the water bucket, a plurality of instantaneous mechanical power densities of the grid area are determined based on transient flow field data of the grid area in an interaction period. The interaction period starts from when the leading edge of the water bucket just cuts into a jet flow and ends when the water bucket completely leaves the jet flow. The instantaneous mechanical power densities of each grid area are integrated in the interaction period, and the total power density value determined is averaged to generate a time-averaged local power density. Based on the time-averaged local power densities of the grid areas on the surface of the water bucket, an evaluation result of the hydraulic work performance of the impulse water turbine is determined. The application realizes quantitative evaluation of the hydraulic work performance of each local area on the surface of the water bucket, and improves the accuracy and comprehensiveness of performance evaluation.

Description

Technical Field

[0001] This application relates to the field of hydropower technology, and more specifically, to a method, apparatus, equipment, and storage medium for evaluating the hydraulic performance of an impulse turbine. Background Technology

[0002] Hydropower, as a high-quality clean and renewable energy source, plays a vital role in the development of a low-carbon economy. Impulse turbines, with their excellent adaptability to high-head and ultra-high-head river basins and superior partial-load operating efficiency, occupy an irreplaceable strategic position in many large-scale hydropower projects located at high altitudes and in complex terrains.

[0003] As the core energy conversion component of an impulse turbine, the hydraulic performance of the runner directly determines the overall efficiency and operational quality of the machine. The working mechanism of an impulse turbine is to periodically impact a rotating water bucket with a high-speed free water jet ejected from a nozzle. This process involves extremely complex jet entry, water flow spreading and deflection, and cut-out and ejection stages, and its internal flow field exhibits typical three-dimensional, highly unsteady, gas-liquid two-phase free surface flow characteristics.

[0004] From the perspective of fluid dynamics and energy conversion, the magnitude of the mechanical energy output by an impulse turbine depends entirely on the momentum exchange and stress distribution between the high-speed water jet and the inner surface of the bucket throughout the entire interaction cycle. Therefore, in the optimization of the hydraulic profile and hydraulic design of the bucket, how to scientifically and accurately quantitatively characterize the contribution of different spatial positions on the bucket surface to the overall work done by the turbine is a key issue in the design and optimization of impulse turbines.

[0005] Therefore, it is particularly important to propose a method for evaluating the working performance of impulse turbines. Summary of the Invention

[0006] In view of this, this application provides a method, apparatus, equipment and storage medium for evaluating the hydraulic performance of an impulse turbine.

[0007] Specifically, this application is implemented through the following technical solution: In a first aspect, embodiments of this application provide a method for evaluating the hydraulic performance of an impulse turbine, including: After the surface of the bucket of the impulse turbine is gridded, for each grid region of the bucket surface, multiple instantaneous mechanical power densities of the grid region are determined based on the transient flow field data of the grid region during the interaction period; wherein the interaction period is from the moment the leading edge of the bucket just enters the jet until the bucket completely leaves the jet. The instantaneous mechanical power density of each grid region is integrated over the interaction period, and the total determined power density is averaged to generate the local power density. The evaluation result of the hydraulic performance of the impulse turbine is determined based on the time-averaged local power density of each grid region on the surface of the water bucket.

[0008] In one optional implementation, determining multiple instantaneous mechanical power densities of the grid region based on transient flow field data of the grid region during the interaction period includes: Based on the transient stress tensor and unit outward normal vector included in the transient process data of the grid region, the surface traction force vector of the grid region is determined; Using the position vector of the grid region and the surface traction force vector, the transient torque vector exerted by the fluid on the grid region is determined; the instantaneous mechanical power density of the grid region is obtained by performing a dot product operation between the transient torque vector and the rotational angular velocity vector.

[0009] In one optional implementation, the transient stress tensor is decomposed into the sum of an isotropic thermodynamic stress tensor and a skewed viscous shear stress tensor. The surface traction force vector is decomposed into: normal pressure traction vector and tangential viscous traction vector.

[0010] In one optional embodiment, the time-averaged local power density includes: a first time-averaged local power density for characterizing the effective work done by the water flow on the surface of the water bucket due to spatial deflection, and a second time-averaged local power density for characterizing the work done by the surface friction force caused by fluid viscosity when the high-speed water film flows along the wall.

[0011] In one optional implementation, the method further includes: Based on the time-averaged local power density of each grid region on the surface of the water bucket, a first spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first time-averaged local power density of each grid region on the surface of the water bucket, a second spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the second time-averaged local power density of each grid region on the surface of the water bucket, a third spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first spatial distribution cloud map, the second spatial distribution cloud map, and the third spatial distribution cloud map, an adjustment strategy for the bucket geometry parameters of the impulse turbine is determined.

[0012] In one alternative implementation, transient flow field data for the grid region is determined according to the following steps: Obtain the geometric parameters, boundary condition parameters, and initial condition parameters of the impulse turbine; Based on the geometric parameters, the boundary condition parameters, and the initial condition parameters, unsteady two-phase flow numerical simulation is performed using computational fluid dynamics to generate global flow field data of the impulse turbine during the interaction period, wherein the global flow field data includes transient flow field data corresponding to multiple grid regions.

[0013] Secondly, embodiments of this application also provide a device for evaluating the hydraulic performance of an impulse turbine, comprising: The first determining module is used to determine multiple instantaneous mechanical power densities of each grid region on the surface of the impeller turbine after the surface of the impeller turbine is gridded, based on the transient flow field data of the grid region during the interaction period; wherein the interaction period is from the moment the leading edge of the impeller cuts into the jet until the impeller completely leaves the jet. The generation module is used to integrate the instantaneous mechanical power density of each grid region within the interaction period, and average the determined total power density to generate a local power density. The second determining module is used to determine the evaluation result of the hydraulic work performance of the impulse turbine based on the time-averaged local power density of each grid region on the surface of the water bucket.

[0014] This application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for evaluating the hydraulic performance of an impulse turbine.

[0015] This application provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method for evaluating the hydraulic performance of an impulse turbine.

[0016] This application proposes a method, apparatus, equipment, and storage medium for evaluating the hydraulic work performance of an impulse turbine. After gridding the surface of the bucket of the impulse turbine, for each grid region on the bucket surface, based on the transient flow field data of the grid region within a defined interaction period, multiple instantaneous mechanical power densities of the grid region within the interaction period are determined. The instantaneous mechanical power density of each grid region is integrated over the interaction period, and the total determined power density is averaged to generate a time-averaged local power density. This time-averaged local power density can accurately reflect the hydraulic work performance of the grid region after the interaction period. After a complete pulsation cycle, the true average net contribution rate to the output shaft power of the runner alleviates the inaccuracy problem of evaluating the runner's work contribution based on the force magnitude at a single moment. Furthermore, based on the time-averaged local power density of each grid region on the bucket surface, the evaluation results of the hydraulic work performance of the impulse turbine can be determined more accurately. Moreover, this application evaluates the work performance of multiple grid regions on the bucket surface separately, that is, it quantitatively analyzes the work situation at different locations on the bucket surface, achieving a more accurate and detailed evaluation of the bucket's work performance, and providing better data support and guidance for the local optimization of the bucket profile. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this specification and form part of this specification, illustrate exemplary embodiments and are used to explain this specification, but do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating an exemplary embodiment of the present application of a method for evaluating the hydraulic performance of an impulse turbine; Figure 2 This is a schematic diagram of an exemplary embodiment of the present application illustrating a hydraulic performance evaluation device for an impulse turbine; Figure 3 This is a schematic diagram of the structure of a computer device provided in this application. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0019] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0021] Research indicates that current technologies for analyzing the internal flow and bucket forces of impulse turbines largely rely on computational fluid dynamics (CFD) to obtain macroscopic parameters and transient distributions of the flow field. However, existing technologies have the following significant drawbacks when guiding refined geometric optimization of the buckets: The lack of quantitative evaluation indicators for local work performance: Traditional performance evaluation methods can usually only calculate the overall macroscopic output power and efficiency of the machine by extracting the total torque on the shaft; or they can only provide the static pressure distribution, water film thickness, or velocity vector diagram of the water bucket surface at a certain transient moment at the microscopic level. These methods cannot quantitatively analyze the work done at different locations on the water bucket surface, which leads to the optimization of the water bucket profile often relying on the designer's engineering experience and lacking reliable data support.

[0022] The inherent unsteady characteristics of impulse turbines are overlooked: the forces acting on the buckets of an impulse turbine are extremely pulsating. Traditional methods, when extracting local forces or torques, often only focus on a few transient moments of the jet impacting the buckets. However, the magnitude of the force at a single moment cannot represent the contribution of that region to the work done by the runner, and lacks consideration of time-averaged integration of transient power over the entire operating cycle.

[0023] Based on this, this application proposes a method, apparatus, equipment, and storage medium for evaluating the hydraulic work performance of an impulse turbine. After gridding the surface of the bucket of the impulse turbine, for each grid region on the bucket surface, based on the transient flow field data of the grid region within a defined interaction period, multiple instantaneous mechanical power densities of the grid region within the interaction period are determined. The instantaneous mechanical power density of each grid region is integrated within the interaction period, and the total determined power density is averaged to generate a time-averaged local power density. This time-averaged local power density can accurately reflect the hydraulic work performance of the grid region within the interaction period. After a complete pulsation cycle, the true average net contribution rate to the output shaft power of the runner is obtained, which alleviates the inaccuracy problem of evaluating the runner's work contribution based on the force magnitude at a single moment. Furthermore, based on the time-averaged local power density of each grid area on the bucket surface, the evaluation results of the hydraulic work performance of the impulse turbine can be determined more accurately. Moreover, this application evaluates the work performance of multiple grid areas on the bucket surface separately, that is, it quantitatively analyzes the work situation at different locations on the bucket surface, realizing a more accurate and detailed evaluation of the bucket's work performance, and providing better data support and guidance for the local optimization of the bucket profile.

[0024] To facilitate understanding of this embodiment, a detailed description of the hydraulic performance evaluation method for an impulse turbine disclosed in this application embodiment is provided first. The execution entity of the hydraulic performance evaluation method for an impulse turbine provided in this application embodiment is generally a computer device with a certain computing capability. This computer device may include, for example, a terminal device, a server, or other processing devices. The terminal device may be user equipment (UE), a mobile device, a user terminal, a computing device, an embedded device, etc. In some possible implementations, the hydraulic performance evaluation method for an impulse turbine can be implemented by a processor calling computer-readable instructions stored in memory.

[0025] See Figure 1 The diagram shows a flowchart of a method for evaluating the hydraulic performance of an impulse turbine according to an embodiment of this application. The method includes steps S101 to S103, wherein: S101. After the surface of the bucket of the impulse turbine is gridded, for each grid area on the surface of the bucket, based on the transient flow field data of the grid area during the interaction period, multiple instantaneous mechanical power densities of the grid area are determined; wherein the interaction period is from the moment the leading edge of the bucket just enters the jet until the bucket completely leaves the jet. S102. Integrate the instantaneous mechanical power density of each grid region within the interaction period, and average the determined total power density to generate the local power density. S103. Based on the time-averaged local power density of each grid region on the surface of the water bucket, determine the evaluation result of the hydraulic performance of the impulse turbine.

[0026] In S101, the surface of the bucket of the impulse turbine is gridded to obtain multiple grid areas on the surface of the bucket. The more grid areas there are, the more detailed the evaluation of the working performance can be.

[0027] For each grid region on the water tank surface, the transient flow field data of the grid region during the interaction period is determined. This transient flow data includes, but is not limited to, the transient stress tensor, unit outward normal vector, and rotational angular velocity vector corresponding to the grid region. The transient flow data can be obtained using computational fluid dynamics (CFD) simulation.

[0028] Optionally, the transient flow field data of the grid region is determined according to the following steps: acquiring the geometric parameters, boundary condition parameters, and initial condition parameters of the impulse turbine; based on the geometric parameters, the boundary condition parameters, and the initial condition parameters, performing unsteady two-phase flow numerical simulation using computational fluid dynamics to generate global flow field data of the impulse turbine during the interaction period, wherein the global flow field data includes transient flow field data corresponding to multiple grid regions respectively.

[0029] Geometric parameters are used to define the geometry of the bucket of the impulse turbine; boundary condition parameters are used to define the flow and pressure of the fluid on the boundary of the computational domain, such as the inlet boundary (e.g., water flow, air pressure) and the outlet boundary; initial condition parameters are used to define the initial state of the entire flow field at the moment the simulation starts.

[0030] Based on the acquired geometric parameters, boundary condition parameters, and initial condition parameters, unsteady two-phase flow numerical simulation is performed using computational fluid dynamics (CFD) to generate global flow field data of the impulse turbine during the interaction cycle. This yields the complete cycle flow data of the impulse turbine's buckets. The global flow field data includes transient flow field data corresponding to multiple grid regions, which can be used to evaluate the work performance of the grid regions in the future.

[0031] After determining the transient flow data of the grid region, the transient flow field data of the grid region within the interaction period are used to determine multiple instantaneous mechanical power densities of the grid region; where the interaction period is from the moment the leading edge of the bucket just enters the jet until the bucket completely leaves the jet. For example, the instantaneous mechanical power density can be obtained by taking the dot product of the torque vector and the rotational angular velocity.

[0032] Optionally, determining multiple instantaneous mechanical power densities of the grid region based on transient flow field data of the grid region during the interaction period includes: determining the surface traction vector of the grid region based on the transient stress tensor and unit outward normal vector included in the transient flow data of the grid region; determining the transient torque vector exerted by the fluid on the grid region using the position vector of the grid region and the surface traction vector; and obtaining the instantaneous mechanical power density of the grid region by performing a dot product operation between the transient torque vector and the rotational angular velocity vector.

[0033] In practice, it is assumed that the impeller of the impulse turbine rotates at a constant angular velocity, and the high-speed free water jet, after being ejected from the nozzle, periodically sweeps across each water bucket. The rotational speed of the impeller is defined as... Its direction is collinear with the rotation axis of the impulse turbine.

[0034] Define the bucket surface as a solid wall boundary condition (no slip condition). Arbitrarily extract a micro-element area (i.e., grid area) dA on the bucket surface, and define the unit outward normal vector of this micro-element surface as N (pointing outward from the bucket wall). At the same time, define the position vector of the center point of this micro-element (i.e., grid area) relative to the turbine's rotation center as r.

[0035] The transient process of the interaction between a high-speed water jet and a water bucket involves three typical stages: jet entry, main jet deflection, and jet exit. During this process, the fluid particle exerts complex forces on the surface element dA of the water bucket. According to the theory of continuum mechanics, the transient stress tensor generated by the fluid at the wall is denoted as... The transient stress tensor The unit outward normal vector of the infinitesimal surface N By performing a dot product operation, the transient, local surface traction force vector exerted by the fluid on the wall element is obtained, denoted as T, and its expression is shown in the following formula (1): (1) The surface traction force vector T includes the transient normal compression and tangential friction exerted by the fluid on the local point, and its value changes with time, producing violent high-frequency pulsations.

[0036] Furthermore, the position vector of the infinitesimal element (i.e., the grid region) can be used. With surface traction vector Performing a cross product yields the transient torque vector exerted by the fluid on the infinitesimal element. As shown in the following formula (2): (2) Then convert the transient torque vector By performing a dot product operation with the rotational angular velocity vector ω, the instantaneous mechanical power density of the grid region is obtained. As shown in formula (3) below: (3) This application achieves the analysis and determination of transient mechanical power density in each grid region on the surface of the water bucket through the above process.

[0037] Research has revealed a shortcoming in related technologies: the failure to distinguish between the effective driving force and surface frictional dissipation. Specifically, the total stress tensor exerted by the fluid on the water tank surface actually includes both the positive pressure generated by fluid deflection (effective driving force) and the surface shear stress caused by fluid viscosity (frictional dissipation force). Existing methods for calculating fluid wall torque typically conflate these two factors, failing to analyze whether the dominant force in a specific region is work-driven or resistance-dissipated.

[0038] This application research found that in impulse turbines, the conversion of fluid kinetic energy into mechanical energy mainly depends on the forced deflection of the water flow by the bucket profile, a process manifested as work done by normal pressure. Meanwhile, the high relative velocity of the fluid generates a large velocity gradient at the wall contact point, leading to tangential viscous friction, a process primarily manifested as energy dissipation. Therefore, this application can utilize the aforementioned transient stress tensor... It can be decomposed into the sum of the isotropic thermodynamic stress tensor and the skewed viscous shear stress tensor, as shown in the following formula (4): (4) in Let I be the transient local static pressure of the flow field at the wall; let I be the second-order unit tensor. This represents the viscous shear stress tensor of the skew.

[0039] Substituting formula (4) into formula (1), the surface traction force vector can be obtained. It is decomposed into: normal pressure traction vector and tangential viscous traction vector, as shown in the following formula (5): (5) in What is obtained is the normal pressure traction vector. What is obtained is the tangential viscous traction vector.

[0040] Furthermore, instantaneous mechanical power density The calculation can be shown in the following formula (6): (6) Research has found that because the buckets of an impulse turbine are in the air for most of the time, momentum exchange only occurs during the brief period of jet impact. A high power density at a particular transient moment does not necessarily mean a large overall contribution to the work done by the turbine at that point. Based on this, this application introduces the concept of "time integral averaging".

[0041] Specifically, the interaction period of a complete water jet and jet is defined as T. cycle That is, the interaction period begins when the leading edge of the water bucket just cuts into the jet and ends when the water bucket completely leaves the jet. In S102, the instantaneous mechanical power density of each grid region is integrated within the interaction period, and the determined total power density is averaged (i.e., divided by the period of the interaction period) to generate the time-averaged local power density. As shown in the following formula (7): (7) The time-averaged local power density represents the true average net contribution rate of a specific spatial location on the surface of the bucket to the output shaft power of the impeller after a complete pulsation cycle. It has a better guiding role in the local optimization of the bucket profile.

[0042] To further facilitate designers in optimizing the geometric parameters of the water bucket, this application utilizes the linear property of integrals to represent the time-averaged local power density. The decomposition follows formula (5), meaning the time-averaged local power density includes: a first time-averaged local power density characterizing the effective work done by the water flow on the surface of the water bucket due to spatial deflection, and a second time-averaged local power density characterizing the work done by the surface friction caused by fluid viscosity when the high-speed water film flows along the wall. This is illustrated in formula (8) below: in, The first time-averaged local power density represents the work done by the squeezing normal force generated on the surface of the water bucket due to spatial deflection. Its expression is shown in equation (9).

[0043] (9) Analysis shows that on a well-designed inner surface of the water hopper, This value should be a significant positive value, representing effective driving work. If a very small positive or even negative value appears on the back surface of the water bucket or in a specific area, it indicates that severe jet interference or backflow has occurred in that area, generating braking torque, and its geometry needs to be optimized.

[0044] in The second time-averaged local power density represents the work done by the surface friction caused by fluid viscosity when the high-speed water film flows along the wall. Its expression is shown in formula (10).

[0045] (10) Analysis shows that, under normal circumstances This negative value represents hydraulic friction loss. By visualizing the spatial distribution of this value using cloud mapping, the high friction dissipation region of the impulse turbine can be precisely located. If a certain area... An abnormally large negative value indicates that the water film at that location is extremely thin and moves at extremely high speed. Frictional hydraulic loss can be reduced by increasing the local wall curvature radius or improving the surface roughness.

[0046] After generating the time-averaged local power density, the evaluation results of the hydraulic performance of the impulse turbine can be determined based on the time-averaged local power density of each grid area on the bucket surface. For example, if the time-averaged local power density is large, the evaluation result indicates that the hydraulic performance is better; conversely, if the time-averaged local power density is small, the evaluation result indicates that the hydraulic performance is poor.

[0047] Optionally, the method further includes: generating a first spatial distribution cloud map on the three-dimensional curved surface of the water bucket based on the time-averaged local power density of each grid region on the water bucket surface; generating a second spatial distribution cloud map on the three-dimensional curved surface of the water bucket based on the first time-averaged local power density of each grid region on the water bucket surface; generating a third spatial distribution cloud map on the three-dimensional curved surface of the water bucket based on the second time-averaged local power density of each grid region on the water bucket surface; and determining an adjustment strategy for the water bucket geometry parameters of the impulse turbine based on the first spatial distribution cloud map, the second spatial distribution cloud map, and the third spatial distribution cloud map.

[0048] This application visualizes the time-averaged local power density of the bucket surface by generating multiple spatial distribution cloud maps. This allows designers to quantitatively evaluate the work performance of the impulse turbine bucket using these multiple 3D visualization cloud maps and determine adjustment strategies for the bucket geometry parameters. For example, adjustment strategies could include, as previously described, increasing the local wall curvature radius at specific grid areas and improving surface roughness to reduce frictional hydraulic losses.

[0049] This application utilizes CFD unsteady two-phase flow numerical simulation to obtain the flow field data of the bucket surface for a complete cycle. Subsequently, using this flow field data, a self-written post-processing script is used to perform the aforementioned vector and time integration operations at each grid node on the bucket surface; the final output is... , , ,as well as , , Distribution cloud map on the three-dimensional curved surface of the water bucket. This enables a quantitative assessment of the work performance of different regions on the water bucket surface.

[0050] This application performs time-averaged processing on the unsteady flow field, accurately quantifying the time-averaged work capacity of each spatial region of the bucket under continuous operation. Addressing the high pulsation frequency characteristic of the impulse turbine flow field, this application constructs a time-averaged integral model of the complete "jet-bucket" interaction cycle. By introducing and extracting the "time-averaged local power density," this application effectively filters out the instantaneous pulsation interference of multiphase flow, quantitatively analyzes the average net work capacity of each region on the bucket surface under continuous operation, and improves the physical rigor of the impulse turbine's work capacity assessment.

[0051] Simultaneously, this application decomposes the total stress tensor to separate the effective driving force and frictional dissipation: Starting from the fundamental principles of continuum mechanics, this application deconstructs the total fluid stress acting on the bucket surface into isotropic pressure and viscous shear stress, and performs independent time-averaged integral calculations for each. This method achieves the separation of the local pressure work and shear dissipation effects in the bucket of an impulse turbine. This decomposition method allows designers to accurately locate the specific spatial distribution of effective driving force and energy dissipation, improving the targeted nature of flow optimization for impulse turbines.

[0052] Corresponding to the aforementioned embodiments of the hydraulic performance evaluation method for impulse turbines, this application also provides embodiments of a hydraulic performance evaluation device for impulse turbines. Figure 2 A schematic diagram of the hydraulic performance evaluation device for an impulse turbine provided in this application specifically includes: The first determining module 201 is used to determine multiple instantaneous mechanical power densities of each grid region on the surface of the impeller after the surface of the impeller is gridded, based on the transient flow field data of the grid region during the interaction period; wherein the interaction period is from the moment the leading edge of the impeller just enters the jet until the impeller completely leaves the jet. The generation module 202 is used to integrate the instantaneous mechanical power density of each grid region within the interaction period, and average the determined total power density to generate a local power density. The second determining module 203 is used to determine the evaluation result of the hydraulic work performance of the impulse turbine based on the time-averaged local power density of each grid area on the surface of the water bucket.

[0053] In an optional implementation, when the first determining module 201 determines multiple instantaneous mechanical power densities of the grid region based on transient flow field data of the grid region during the interaction period, it is used to: Based on the transient stress tensor and unit outward normal vector included in the transient process data of the grid region, the surface traction force vector of the grid region is determined; Using the position vector of the grid region and the surface traction force vector, the transient torque vector exerted by the fluid on the grid region is determined; the instantaneous mechanical power density of the grid region is obtained by performing a dot product operation between the transient torque vector and the rotational angular velocity vector.

[0054] In one optional implementation, the transient stress tensor is decomposed into the sum of an isotropic thermodynamic stress tensor and a skewed viscous shear stress tensor. The surface traction force vector is decomposed into: normal pressure traction vector and tangential viscous traction vector.

[0055] In one optional embodiment, the time-averaged local power density includes: a first time-averaged local power density for characterizing the effective work done by the water flow on the surface of the water bucket due to spatial deflection, and a second time-averaged local power density for characterizing the work done by the surface friction force caused by fluid viscosity when the high-speed water film flows along the wall.

[0056] In an optional embodiment, the apparatus further includes: a third determining module 204, configured to: Based on the time-averaged local power density of each grid region on the surface of the water bucket, a first spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first time-averaged local power density of each grid region on the surface of the water bucket, a second spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the second time-averaged local power density of each grid region on the surface of the water bucket, a third spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first spatial distribution cloud map, the second spatial distribution cloud map, and the third spatial distribution cloud map, an adjustment strategy for the bucket geometry parameters of the impulse turbine is determined.

[0057] In one optional implementation, the first determining module 201 is used to determine the transient flow field data of the grid region according to the following steps: Obtain the geometric parameters, boundary condition parameters, and initial condition parameters of the impulse turbine; Based on the geometric parameters, the boundary condition parameters, and the initial condition parameters, unsteady two-phase flow numerical simulation is performed using computational fluid dynamics to generate global flow field data of the impulse turbine during the interaction period, wherein the global flow field data includes transient flow field data corresponding to multiple grid regions.

[0058] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0059] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0060] This application also provides a computer-readable storage medium storing a computer program that can be used to execute the hydraulic performance evaluation method for impulse turbines described in the above embodiments.

[0061] This application also provides a computer device, see [link to relevant documentation] Figure 3 The diagram shown illustrates the structure of the computer device provided in this application. At the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the hydraulic performance evaluation method for the impulse turbine described in the above embodiments. Of course, besides software implementation, this specification does not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. That is to say, the execution entity of the following processing flow is not limited to individual logic units, but can also be hardware or logic devices.

[0062] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs) containing computer-usable program code. The form of a computer program product implemented on ROM, optical memory, etc.

[0063] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0064] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0065] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes. In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0066] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0067] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, and optical disc read-only memory (CD). ROM, digital multifunction optical disc (DVD) or other optical storage, magnetic cassette tape, magnetic magnetic disk storage or other magnetic storage devices or any other non-transferable medium, may be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0068] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0069] This specification can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This specification can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0070] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0071] The embodiments of the subject matter and functional operation described in this specification can be implemented in the following ways: digital electronic circuits, tangibly embodied computer software or firmware, computer hardware including the structures disclosed in this specification and their structural equivalents, or combinations thereof. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible, non-transitory program carrier for execution by a data processing apparatus or for controlling the operation of a data processing apparatus. Alternatively or additionally, the program instructions may be encoded on artificially generated propagation signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information and transmit it to a suitable receiving device for execution by the data processing apparatus. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or combinations thereof.

[0072] The processing and logic flow described in this specification can be executed by one or more programmable computers that execute one or more computer programs to perform corresponding functions by operating on input data and generating output. The processing and logic flow can also be executed by dedicated logic circuitry—such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits), and the device can also be implemented as dedicated logic circuitry.

[0073] Suitable computers for executing computer programs include, for example, general-purpose and / or special-purpose microprocessors, or any other type of central processing unit. Typically, the central processing unit receives instructions and data from read-only memory and / or random access memory. The basic components of a computer include a central processing unit for implementing or executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as disks, magneto-optical disks, or optical disks, or the computer will be operatively coupled to such mass storage devices to receive data from or transfer data to them, or both. However, a computer is not required to have such devices. Furthermore, a computer can be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device such as a universal serial bus (USB) flash drive, to name a few.

[0074] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), magnetic disks (e.g., internal hard disks or removable disks), magneto-optical disks, and CDs. ROM and DVD ROM disk. The processor and memory can be supplemented by or integrated into dedicated logic circuitry.

[0075] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily intended to describe features of specific embodiments of a particular invention. Certain features described in the various embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation thereof.

[0076] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0077] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings are not necessarily shown in a specific order or sequence to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0078] The above description is merely 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 scope of protection of this application.

Claims

1. A method for evaluating the hydraulic performance of an impulse turbine, characterized in that, The method includes: After the surface of the bucket of the impulse turbine is gridded, for each grid region of the bucket surface, multiple instantaneous mechanical power densities of the grid region are determined based on the transient flow field data of the grid region during the interaction period; wherein the interaction period is from the moment the leading edge of the bucket just enters the jet until the bucket completely leaves the jet. The instantaneous mechanical power density of each grid region is integrated over the interaction period, and the total determined power density is averaged to generate the local power density. The evaluation result of the hydraulic performance of the impulse turbine is determined based on the time-averaged local power density of each grid region on the surface of the water bucket.

2. The method according to claim 1, characterized in that, The determination of multiple instantaneous mechanical power densities of the grid region based on transient flow field data of the grid region during the interaction period includes: Based on the transient stress tensor and unit outward normal vector included in the transient process data of the grid region, the surface traction force vector of the grid region is determined; Using the position vector of the grid region and the surface traction force vector, the transient torque vector exerted by the fluid on the grid region is determined; the instantaneous mechanical power density of the grid region is obtained by performing a dot product operation between the transient torque vector and the rotational angular velocity vector.

3. The method according to claim 2, characterized in that, The transient stress tensor is decomposed into the sum of an isotropic thermodynamic stress tensor and a skewed viscous shear stress tensor. The surface traction force vector is decomposed into: normal pressure traction vector and tangential viscous traction vector.

4. The method according to claim 3, characterized in that, The time-averaged local power density includes: a first time-averaged local power density used to characterize the effective work done by the water flow on the surface of the water bucket due to spatial deflection, and a second time-averaged local power density used to characterize the work done by the surface friction force caused by fluid viscosity when the high-speed water film flows along the wall.

5. The method according to claim 4, characterized in that, The method further includes: Based on the time-averaged local power density of each grid region on the surface of the water bucket, a first spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first time-averaged local power density of each grid region on the surface of the water bucket, a second spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the second time-averaged local power density of each grid region on the surface of the water bucket, a third spatial distribution cloud map is generated on the three-dimensional curved surface of the water bucket. Based on the first spatial distribution cloud map, the second spatial distribution cloud map, and the third spatial distribution cloud map, an adjustment strategy for the bucket geometry parameters of the impulse turbine is determined.

6. The method according to claim 1, characterized in that, Determine the transient flow field data for the grid region using the following steps: Obtain the geometric parameters, boundary condition parameters, and initial condition parameters of the impulse turbine; Based on the geometric parameters, the boundary condition parameters, and the initial condition parameters, unsteady two-phase flow numerical simulation is performed using computational fluid dynamics to generate global flow field data of the impulse turbine during the interaction period, wherein the global flow field data includes transient flow field data corresponding to multiple grid regions.

7. A device for evaluating the hydraulic work performance of an impulse turbine, characterized in that, The device includes: The first determining module is used to determine multiple instantaneous mechanical power densities of each grid region on the surface of the impeller turbine after the surface of the impeller turbine is gridded, based on the transient flow field data of the grid region during the interaction period; wherein the interaction period is from the moment the leading edge of the impeller cuts into the jet until the impeller completely leaves the jet. The generation module is used to integrate the instantaneous mechanical power density of each grid region within the interaction period, and average the determined total power density to generate a local power density. The second determining module is used to determine the evaluation result of the hydraulic work performance of the impulse turbine based on the time-averaged local power density of each grid region on the surface of the water bucket.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the steps of the method according to any one of claims 1-6.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor performs the steps of the method according to any one of claims 1-6.

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