Shielding main pump impeller flow field load time-space domain conversion method and system

Abstract

The embodiment of the invention provides a shielding main pump impeller flow field load time-space domain conversion method and system, and the method can carry out the fluid dynamics analysis calculation of a three-dimensional water body model after the three-dimensional water body model and an impeller structure model are constructed, and obtains an unsteady flow field result. And then impeller flow field load time-space domain conversion is executed according to an unsteady flow field result, the unsteady flow field result obtained through CFD analysis is imported and loaded into a structure field through the point cloud technology, and transmission and application of the structure surface flow field load are completed. A hydrodynamic force load and a centrifugal force load are applied through finite element analysis, stress response analysis is carried out on the main pump blade under the transient working condition, and fatigue life calculation is carried out on a stress response analysis result under the unsteady working condition. According to the method, analysis is carried out through a complex simulated load, a fatigue life analysis process and an evaluation system are established, and the problem that the hydraulic load of the main pump impeller cannot be accurately loaded can be solved.

Description

Technical Field

[0001] This application relates to the field of computer-aided analysis technology, and in particular to a method and system for spatiotemporal conversion of flow field load on a shielded main pump impeller. Background Technology

[0002] The closed-loop test of a canned motor pump is an experimental method used to study the performance and flow characteristics of a main pump in a closed-loop system. The closed-loop test system can be used to optimize pump design and performance, improve application efficiency in various fields, and provide data support for the performance verification of special pumps such as nuclear main pumps. In the closed-loop test of a canned motor pump, the occurrence of blade breakage raises renewed concerns about the safety of nuclear main pump impellers, necessitating an analysis of the operational safety and reliability of the canned motor pump impeller.

[0003] To determine the operational reliability of the nuclear main pump impeller, stress analysis can be performed on the impeller. During stress analysis, a structural model of the impeller can be established, and the material properties and boundary conditions of the impeller model can be defined. Based on the defined conditions, loads such as centrifugal loads and fluid pressure loads are simulated and applied to the impeller model. This allows for the analysis and calculation of the stress distribution of the impeller under simulated loads, and an assessment of whether the stress level meets the design operational reliability requirements of the impeller.

[0004] Because the stress analysis of the pump impeller only considers centrifugal load and neglects the influence of hydraulic load on impeller strength and fatigue, the calculation results have significant errors. Detailed and accurate three-dimensional stress calculations and fatigue safety assessments of the impeller are required, and the stress intensity and fatigue service life of the impeller under water pulsating pressure must be considered when the load changes over time. This complicates the analysis process and results in low accuracy. Furthermore, when performing stress intensity and fatigue analysis of the canned motor pump, the hydraulic load on the impeller cannot be accurately applied. Summary of the Invention

[0005] In view of this, embodiments of this application provide a method and system for spatiotemporal conversion of flow field load on a shielded main pump impeller, in order to solve the problem that the hydraulic load on the impeller of a shielded main pump cannot be accurately applied when performing stress intensity and fatigue analysis of a shielded main pump.

[0006] According to one aspect of this application, a method for spatiotemporal conversion of flow field load on a shielded main pump impeller is provided, the method comprising: An analysis model is constructed, which includes a three-dimensional water body model and an impeller structure model; Fluid dynamics analysis and calculations are performed on the three-dimensional water body model to obtain unsteady flow field results, including blade surface pressure data. Based on the unsteady flow field results, perform a spatiotemporal transformation of the impeller flow field load to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model; Based on the principle of finite element analysis, transient dynamic analysis is performed on the impeller structure model under preset simulated load conditions to generate stress response analysis results. The simulated loads include hydrodynamic loads and centrifugal loads. Fatigue life is calculated based on the stress response analysis results.

[0007] In some embodiments, constructing an analysis model includes: Obtain the two-dimensional structure diagram; A three-dimensional water body model is established based on the two-dimensional structure diagram, and a computational domain is created for the three-dimensional water body model to obtain a computational domain three-dimensional water body model. Based on the principles of computational fluid dynamics, the three-dimensional water body model of the computational domain is divided into fluid meshes.

[0008] In some embodiments, performing fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results includes: Acquire calculation setting data, which includes one or more combinations of working medium data, calculation equation and turbulence model selection data, reference data, rotating domain data, inlet and outlet boundary condition data, convergence data, initial calculation field data, and output setting data; Set the calculation requirements information according to the calculation settings data; Obtain the number of blades of the main pump impeller and the current hardware configuration information, wherein the number of blades includes the number of moving blades and the number of stationary blades of the main pump impeller; The time step is determined according to the current hardware configuration information. The transient calculation of the flow field in the computational domain is performed based on the number of blades, the computational requirements, and the time step.

[0009] In some embodiments, performing fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results further includes: Obtain the results of transient calculations of the flow field in the computational domain; Select the target blade and static pressure setting in the main pump impeller, wherein the target blade is one of the multiple blades of the main pump impeller; The target blade's surface pressure data is output according to the static pressure settings. The blade surface pressure data includes node coordinates and static pressure values. The node coordinates are the coordinates of the fluid grid nodes arranged on the surface of the target blade. The static pressure values ​​are related to the node coordinates.

[0010] In some embodiments, performing a spatiotemporal transformation of the impeller flow field load based on the unsteady flow field results includes: The load steps are set, including structural load steps and fluid load steps, and the structural load steps and the fluid load steps are kept consistent. Multiple structural field coordinates are selected, where the structural field coordinates are the position coordinates in the structural field corresponding to the fluid field coordinates of the impeller structural model; Based on the selected multiple structural field coordinates, coordinate transformation is performed on the pressure field structural data to obtain unsteady pulsating pressure data; The unsteady pulsating pressure data is projected onto the structural mesh of the impeller structure model.

[0011] In some embodiments, the method further includes: Develop spatiotemporal transformation rules for impeller flow field loads; Extract pressure data numbers, which are used to characterize the numbers corresponding to the fluid grids in the impeller flow field load; the pressure data numbers include start numbers and end numbers; Pressure data is extracted from the pressure field structure data based on the pressure data number; Determine the replication number, which is used to characterize the number corresponding to the structural mesh in the impeller structure model; Based on the spatiotemporal domain conversion rule of the impeller flow field load, the pressure data is imported into the structural mesh corresponding to the replication number.

[0012] In some embodiments, based on the principle of finite element analysis, transient dynamic analysis is performed on the impeller structure model under preset simulated load conditions to generate stress response analysis results, including: Define the input and output data for transient dynamic analysis. The input data is load data based on a time function. The output data is a time-varying derived quantity, which includes at least displacement data. The impeller rotation is divided into load steps, the same as in computational fluid dynamics analysis. Based on the input data and the simulated load, a transient dynamic stress response analysis is performed to obtain the impeller stress analysis results for the load step; According to the output data, stress data at key node locations are selected from the impeller stress analysis results. The stress data at key node locations are used to characterize the stress change over time during one revolution of the impeller. The key node locations are the node locations where the blade inlet and blade outlet intersect with the shaft disk and cover disk.

[0013] In some embodiments, calculating fatigue life based on the stress response analysis results includes: Select a fatigue point, and extract the maximum and minimum alternating stresses of the fatigue point within the impeller analysis cycle from the stress response analysis results; Goodman curves are generated based on the maximum alternating stress and the minimum alternating stress; Based on the stress correction principle, the position of the fatigue point in the Goodman curve is determined; Fatigue life is calculated based on the location of the fatigue point in the Goodman curve.

[0014] In some embodiments, calculating fatigue life based on the position of the fatigue point in the Goodman curve includes: Obtain the impeller material of the main pump impeller and the stress-life curve corresponding to the impeller material; The stress amplitude is calculated based on the maximum alternating stress and the minimum alternating stress, and the stress amplitude is used to characterize the difference between the maximum alternating stress and the minimum alternating stress and the average stress, respectively. The stress amplitude is corrected using the Goodman curve. On the stress-life curve, find the number of cycles corresponding to the corrected stress amplitude to obtain the fatigue life.

[0015] According to another aspect of this application, a spatiotemporal conversion system for the flow field load of a shielded main pump impeller is provided, the system comprising: The model building module is used to build the analysis model, which includes a three-dimensional water body model and an impeller structure model. The first calculation module is used to perform fluid dynamics analysis and calculation on the three-dimensional water body model to obtain unsteady flow field results, including blade surface pressure data. The conversion module is used to perform spatiotemporal domain conversion of the impeller flow field load based on the unsteady flow field results, so as to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model; The second calculation module is used to perform transient dynamic analysis on the impeller structure model based on the finite element analysis principle and under preset simulated load conditions to generate stress response analysis results. The simulated loads include hydrodynamic loads and centrifugal loads. The fatigue life output module calculates the fatigue life based on the stress response analysis results.

[0016] According to another aspect of this application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the program to implement the above-described method for spatiotemporal conversion of the flow field load of the shielded main pump impeller.

[0017] According to another aspect of this application, a storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the above-described method for spatiotemporal conversion of the flow field load of the shielded main pump impeller.

[0018] By employing the above technical solutions, this application provides a method and system for spatiotemporal conversion of flow field loads on a shielded main pump impeller. The method involves constructing a three-dimensional water body model and an impeller structure model, performing fluid dynamics analysis on the three-dimensional water body model to obtain unsteady flow field results. Then, based on the unsteady flow field results, a spatiotemporal conversion of the impeller flow field loads is performed. Point cloud technology is used to import and load the unsteady flow field results obtained from CFD analysis into the structural field, completing the transfer and application of flow field loads on the structural surface. Furthermore, hydrodynamic and centrifugal loads are applied through finite element analysis to perform stress response analysis on the main pump blades under transient conditions, enabling fatigue life calculation based on the stress response analysis results under unsteady conditions. This method uses complex simulated loads for analysis and establishes a fatigue life analysis process and evaluation system, solving the problem of inaccurate loading of hydraulic loads on the main pump impeller.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the impeller structure provided in an embodiment of this application; Figure 2 This is a schematic flowchart of the spatiotemporal domain conversion method for the flow field load of the shielded main pump impeller provided in an embodiment of this application; Figure 3 A flowchart of impeller stress and fatigue analysis provided for embodiments of this application; Figure 4 This is a schematic diagram of pressure distribution provided for an embodiment of this application; Figure 5 This is a schematic diagram of the spatiotemporal conversion process of the impeller flow field load provided in an embodiment of this application; Figure 6 The stress-time variation diagram provided for the embodiments of this application; Figure 7 This is a schematic diagram of the fatigue failure discrimination criteria provided in the embodiments of this application; Figure 8This is a schematic diagram of the high-cycle fatigue analysis and evaluation results provided in the embodiments of this application; Figure 9 A schematic diagram of the spatiotemporal domain conversion system for the flow field load of the shielded main pump impeller provided in this application embodiment. Detailed Implementation

[0021] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0022] In this embodiment, the main pump refers to a device used for conveying fluids in an industrial system. The main pump can undertake core conveying tasks in nuclear reactor cooling systems, large industrial circulation systems, or important process flows.

[0023] Depending on the application, main pumps can have different sizes and structures. Taking nuclear main pumps as an example, they are core equipment in nuclear reactor cooling systems, used to drive the circulation of coolants such as water or liquid metal between the reactor pressure vessel and the steam generator to remove the heat generated by the reactor. Nuclear main pumps can be divided into canned main pumps and shaft-sealed main pumps. The canned nuclear main pump, also known as a shielded main pump, integrates the motor with the pump body, adopts a shaft-sealed structure, and relies on a shielding sleeve to isolate the motor from the fluid to avoid leakage risks.

[0024] In some embodiments, the canned motor main pump includes a pump body, impeller, canned motor, lubrication device, circulation pipe, sealing device, support components, etc. For example, Figure 1 As shown, a shielded motor includes a stator and a rotor. The stator and rotor are isolated by a shielding sleeve. The stator windings are outside the shielding sleeve, and the rotor is inside the shielding sleeve. Power is transmitted through a magnetic field. The rotor is connected to an impeller to drive the impeller to rotate. The impeller is the core component of the pump, located inside the pump body. It generates centrifugal force through rotation, giving energy to the fluid and allowing it to be discharged.

[0025] The main pump impeller achieves fluid transport and pressurization through rotational motion. Based on centrifugal force, as the impeller rotates at high speed, the fluid is thrown towards the outer edge of the impeller, gaining both kinetic and pressure energy. During impeller rotation, a low-pressure zone forms at the impeller center, drawing fluid into the pump, while at the outer edge, the fluid is compressed and discharged. As the fluid flows within the impeller, dynamic pressure energy is converted into static pressure energy through a diffuser or volute, thus pressurizing the fluid.

[0026] As the core component of a canned motor pump, the main pump impeller has stringent design requirements. In some embodiments, the impeller design needs to comprehensively consider factors such as fluid dynamics, mechanical strength, and operating efficiency. For example, the main pump impeller can be designed based on a three-segment, four-stage load control design method. This involves dividing the load distribution of the impeller blades into three segments: the inlet segment, the intermediate segment, and the outlet segment, and using a quadratic function to control the load distribution in each segment, thereby optimizing the impeller's structure and performance. Alternatively, multi-parameter design can be used, employing computer-aided design applications such as BladeGen for three-dimensional multi-parameter design, adjusting geometric parameters such as blade wrap angle and thickness to optimize the impeller's hydraulic performance. Finally, axial-flow impeller design can be employed, specifically for nuclear main pumps using axial-flow impellers, focusing on the streamlined structure of the blades and the optimization of the hub to improve efficiency and reduce energy loss.

[0027] In some embodiments, when designing the main pump impeller, a canned motor pump closed-loop test is required for the designed structure. The canned motor pump closed-loop test is an experimental method used to study the performance and flow characteristics of the main pump in a closed-loop system. Closed-loop tests can be used to optimize pump design and performance, improve application efficiency in various fields, and provide data support for the performance verification of special pumps such as nuclear main pumps.

[0028] When conducting a closed-loop test, the experimental system must first be set up. This involves selecting equipment such as the canned motor pump, circulation piping, heat exchanger, flow meter, and pressure sensor, and then constructing the closed-loop experimental system according to the experimental requirements. Next, the canned motor pump is started according to the operating procedures, and the outlet valve is gradually adjusted to bring the system to the predetermined operating conditions. After starting the canned motor pump, the monitoring equipment in the experimental system can record parameters such as pressure, flow rate, temperature, and vibration in real time, ensuring the accuracy and completeness of the data.

[0029] To perform flow rate and head testing, flow meters and pressure sensors can be used to measure the flow rate and head of the canned motor pump under different operating conditions. For vibration and noise testing, the vibration velocity and noise level of the canned motor pump during operation can be measured to ensure they are within acceptable limits. The temperature of the cooling system and pump body can also be monitored to ensure the temperature is within the design range.

[0030] By monitoring real-time data, the collected data can be organized and analyzed to calculate the performance parameters of the canned motor pump. The experimental results are then compared with design parameters or theoretical values ​​to verify whether the performance of the canned motor pump meets the requirements. For example, in a closed-loop test of the canned motor pump, if the pump blades break, it indicates that the current design safety of the pump impeller is low; therefore, it is necessary to analyze the operational safety and reliability of the canned motor pump impeller.

[0031] To determine the operational reliability of the nuclear main pump impeller, stress analysis can be performed on the impeller in some embodiments. During stress analysis, a structural model of the impeller can be established, and the material properties and boundary conditions of the impeller model can be defined. Based on the defined conditions, loads such as centrifugal loads and fluid pressure loads are simulated and applied to the impeller model. This allows for the analysis and calculation of the stress distribution of the impeller under simulated loads, and an assessment of whether the stress level meets the design operational reliability requirements of the impeller.

[0032] However, because the stress analysis of the pump impeller only considers centrifugal load and neglects the influence of hydraulic load on impeller strength and fatigue, the calculation results have significant errors. Detailed and accurate three-dimensional stress calculations and fatigue safety assessments of the impeller are required, and the stress intensity and fatigue service life of the impeller under water pulsating pressure must be considered when the load changes over time. This leads to a complex analysis process and low accuracy of the data analysis results. Furthermore, when performing stress intensity and fatigue analysis of the canned motor pump, the hydraulic load on the canned motor pump impeller cannot be accurately applied.

[0033] To address the problem of inaccurate loading of hydraulic loads on the impeller of a canned main pump during stress intensity and fatigue analysis, this application provides a method for spatiotemporal conversion of the flow field load on the impeller of a canned main pump in some embodiments, such as... Figure 2 As shown, the method includes: S101. Construct the analysis model.

[0034] To perform stress intensity and fatigue analysis on the impeller of the canned motor pump, an analysis model needs to be constructed in advance based on the design structure. This analysis model includes a three-dimensional water body model and an impeller structure model. The three-dimensional water body model is a three-dimensional geometric model used to simulate the flow characteristics of water during computational fluid dynamics (CFD) analysis. The three-dimensional water body model can be used to analyze the flow behavior of water under specific conditions, such as velocity field, pressure distribution, and temperature field.

[0035] In some embodiments, to construct a three-dimensional water body model, an electronic device with data processing capabilities can acquire a two-dimensional structure diagram during the construction of the analysis model, then establish a three-dimensional water body model based on the two-dimensional structure diagram, and create a computational domain for the three-dimensional water body model to obtain a computational domain three-dimensional water body model. Then, based on the principles of computational fluid dynamics, a fluid mesh is generated for the computational domain three-dimensional water body model.

[0036] In this context, a two-dimensional drawing refers to a design drawing created using planar drawing tools. After creating the planar design drawing, it can be converted into a three-dimensional structural drawing using three-dimensional modeling tools. After establishing the three-dimensional water model, a computational domain is then created for it. The computational domain, defined in CFD simulations, is the region of fluid flow; it is a three-dimensional space encompassing all the physical processes of the fluid. When creating the computational domain, its boundaries must first be clearly defined, including the fluid inlet, outlet, and solid walls. Then, the physical properties of the fluid within the computational domain, such as density, viscosity, and thermal conductivity, are defined. Finally, the initial states of the computational domain are set, including the initial velocity, pressure, and temperature of the fluid.

[0037] After creating the computational domain, the 3D water model of the computational domain needs to be meshed based on computational fluid dynamics principles. A mesh divides the computational domain into a series of small, discrete elements (mesh cells) to facilitate numerical solutions to the fluid dynamics equations. When meshing, a suitable mesh type must first be selected based on the complexity of the geometric model and the simulation requirements. Then, mesh parameters are set to define the size, shape, and distribution of the mesh. Finally, mesh generation tools such as ANSYS Meshing and ICEM CFD are used to generate the mesh.

[0038] For example, to calculate the fatigue strength of the main pump impeller and obtain the surface pressure of the impeller blades at different times, CFD applications can be used to perform transient calculations on the flow field of the computational domain. Before performing transient calculations, a three-dimensional water body model of the computational domain needs to be established based on the two-dimensional diagram, and a computational domain mesh model needs to be established using CFD preprocessing applications.

[0039] The impeller structure model is a virtual model constructed based on the designed main pump impeller structure. In some embodiments, the impeller structure model can be created using 3D drawing tools. For example, design parameters, including the number of blades, blade angles, hub ratio, and blade thickness distribution, can be input using the attribute editor of the drawing tool, and parametric details such as the leading edge, trailing edge, and thickness distribution of the blades can be defined.

[0040] To perform subsequent structural analysis, the impeller structure model also needs to be meshed during its construction. This meshing can be done using point cloud techniques from the finite element analysis principles.

[0041] S102. Perform fluid dynamics analysis and calculation on the three-dimensional water body model to obtain unsteady flow field results.

[0042] like Figure 3As shown, after constructing the analysis model, fluid dynamics analysis calculations can be performed on the three-dimensional water body model. Fluid dynamics analysis is a numerical analysis method that uses computer simulations of fluid flow. By solving the basic equations of fluid dynamics, the behavior of fluids under different conditions can be predicted, including characteristics such as velocity, pressure, temperature, and turbulence. Therefore, performing fluid dynamics analysis calculations on the three-dimensional water body model can obtain unsteady flow field results. These unsteady flow field results include blade surface pressure data.

[0043] In some embodiments, when the data processing device performs fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results, it may first acquire calculation setting data. This calculation setting data includes one or more combinations of working medium data, calculation equations and turbulence model selection data, reference data, rotating domain data, inlet and outlet boundary condition data, convergence data, initial calculation field data, and output setting data.

[0044] For example, calculation settings are required before performing fluid dynamics analysis calculations. These settings may include working medium settings, selection of calculation equations and turbulence models, reference pressure and reference length settings, rotation domain settings, inlet and outlet boundary condition settings, convergence settings, initial field settings, and output settings.

[0045] After acquiring the computational setup data, computational requirements can be set based on this data, including boundary conditions and other data for the fluid dynamics analysis process. The number of blades on the main pump impeller and the current hardware configuration information are acquired, and the time step is determined according to the current hardware configuration. Transient flow field calculations in the computational domain are then performed based on the number of blades, the computational requirements, and the time step. The number of blades includes both the number of moving and stationary blades on the main pump impeller. In other words, the time step is determined based on the number of moving and stationary blades, the computational requirements, and the computer hardware conditions to complete the transient flow field calculations in the computational domain.

[0046] In some embodiments, when the data processing device performs fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results, it can also acquire the result data of transient flow field calculations in the computational domain and select the target blade and static pressure settings in the main pump impeller. Then, it outputs the blade surface pressure data of the target blade according to the static pressure settings. The target blade is one of multiple blades in the main pump impeller. The blade surface pressure data includes node coordinates and static pressure values; the node coordinates are the coordinates of fluid grid nodes arranged on the surface of the target blade; the static pressure value is correlated with the node coordinates.

[0047] For example, after completing the transient calculation and obtaining the results of the transient flow field calculation in the computational domain, the calculation results can be post-processed to extract blade surface pressure data. During post-processing, first open the file to be post-processed, select the blade from the "surfaces" section of the file to extract data, and then select the static pressure option from the "Quantities" section of the file to output the pressure data for the selected surface. The output pressure data can include four columns: the first three columns are the coordinates of the grid nodes arranged on the selected blade surface, and the fourth column is the static pressure value of the corresponding coordinate node.

[0048] The unsteady flow field results obtained by performing fluid dynamics analysis on a three-dimensional water model can be used as input data for subsequent finite element analysis processes in finite element analysis tools such as ANSYS.

[0049] S103. Perform a spatiotemporal domain transformation of the impeller flow field load based on the unsteady flow field results, so as to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model.

[0050] Using the unsteady flow field results obtained from CFD analysis, the pressure data distribution at different times and locations can be obtained. Since the analysis domain rotates and changes in both time and space during CFD flow field analysis, the extracted pressure data also varies according to the load time and the different positions of the blades. However, in structural analysis, the impeller position is fixed, and the transient analysis load can only change with the load time. Therefore, it is necessary to import the pressure data from CFD into the structural analysis. This requires performing a spatiotemporal domain transformation of the impeller flow field load based on the unsteady flow field results to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structural model.

[0051] In some embodiments, when performing spatiotemporal transformation of the impeller flow field load based on the unsteady flow field results, the load step number can be set first. This load step number includes structural load steps and fluid load steps, and the structural load steps and fluid load steps are kept consistent. Then, multiple structural field coordinates are selected. These structural field coordinates are the position coordinates in the structural field corresponding to the fluid field coordinate positions of the impeller structural model. Next, coordinate transformation is performed on the pressure field structural data according to the selected structural field coordinates to obtain unsteady pulsating pressure data. Finally, the unsteady pulsating pressure data is projected onto the structural mesh of the impeller structural model.

[0052] For example, such as Figure 4As shown, when the data processing equipment performs spatiotemporal conversion of the main pump impeller flow field load, it can keep the load steps of the structure and the load steps of the fluid consistent. Then, it selects the coordinates corresponding to the coordinate positions of the structural field and the fluid field as input data, converts the pressure field structural data according to the data with consistent coordinates, and loads the load data onto the corresponding blades.

[0053] Because the amount of data involved in data transformation is large, spatiotemporal conversion rules for impeller flow field loads can be developed, and data transformation can be performed based on these rules. In some embodiments, spatiotemporal conversion rules for impeller flow field loads can be developed first, i.e., a conversion program corresponding to the spatiotemporal conversion process of impeller flow field loads can be developed. By extracting the pressure data number and replication number, the pressure data is imported into the structural mesh corresponding to the replication number based on the impeller flow field load spatiotemporal conversion rules. The pressure data number is used to characterize the number corresponding to the fluid mesh in the impeller flow field load; the pressure data number includes a start number and an end number; therefore, pressure data can be extracted from the pressure field structural data based on the pressure data number. The replication number is used to characterize the number corresponding to the structural mesh in the impeller structural model.

[0054] For example, such as Figure 5 As shown, the pressure data numbering can be determined to include a starting number of 94 and an ending number of 130, with the copy number being 26. Therefore, pressure data from numbers 94-130 can be copied according to the pressure data from number 26 for data import, projecting the unsteady pulsating pressure data onto the structural analysis mesh. Furthermore, point cloud technology can be used to transfer and apply flow field loads on the structural surface within a unified coordinate system and units, ensuring the effectiveness and accuracy of data transfer.

[0055] S104. Based on the principle of finite element analysis, under preset simulated load conditions, a transient dynamic analysis is performed on the impeller structure model to generate stress response analysis results.

[0056] After performing the spatiotemporal transformation of the impeller flow field load, the data processing equipment can also perform transient dynamic analysis on the impeller structure model based on the finite element analysis principle. Transient dynamic analysis can be used to determine the structure's response under load changes at any time; it is also known as time history analysis.

[0057] During transient dynamic analysis, finite element analysis tools can apply simulated loads to the impeller structure model. These simulated loads can include hydrodynamic loads and centrifugal loads. Hydrodynamic loads refer to the forces exerted by the fluid on solid boundaries during motion. Hydrodynamic loads can originate from the fluid's kinematic characteristics, including pressure and shear stress. Centrifugal loads are inertial forces generated by the impeller's rotational motion. Centrifugal loads can act on rotating components and are caused by the outward inertial force exerted on the blades during rotation due to the fluid's mass.

[0058] After applying simulated loads, transient dynamic analysis can be performed on the impeller structure model under the applied preset simulated load conditions to generate stress response analysis results. In some embodiments, when performing transient dynamic analysis on the impeller structure model, the input and output data of the transient dynamic analysis can be defined first. The input data is load data based on a time function; the output data is a derived quantity that varies with time, and the derived quantity includes at least displacement data. That is, in the transient dynamic analysis process, the input data is the load as a time function, and the output data is derived quantities such as displacement that vary with time, thereby considering periodic hydrodynamic loads and centrifugal loads to perform transient dynamic stress response analysis on the main pump impeller.

[0059] After defining the input and output data, one revolution of the impeller can be divided into load steps, similar to those used in computational fluid dynamics analysis. Transient dynamic stress response analysis is then performed based on the input data and the simulated load to obtain the impeller stress analysis results for each load step. Next, according to the output data, stress data at key node locations are selected from the impeller stress analysis results. These key node locations characterize the stress variation over time during one revolution of the impeller; the key node locations are the points where the blade inlet and outlet intersect with the shaft disk and cover disk.

[0060] For example, to view the impeller stress analysis results for each load step, one revolution of the impeller can be divided into the same load steps as the CFD fluid analysis. The stress variation over time within one revolution of the impeller can be observed at the node locations where the blade inlet and outlet intersect with the shaft disk and cover disk. Figure 6 As shown.

[0061] S105. Calculate fatigue life based on the stress response analysis results.

[0062] After performing transient dynamic analysis on the impeller structural model to generate stress response analysis results, fatigue life can be calculated based on these results. In impeller fatigue failure problems, the material properties of the impeller must be considered first. During manufacturing, defects or cracks may exist in areas where the impeller material changes or in geometrically sensitive areas, requiring in-depth investigation into the causes of crack propagation. Mechanical loads are a significant cause of impeller failure. In addition to mechanical loads, the impeller is also subjected to hydrodynamic cyclic loads. Under alternating loads, alternating stresses are generated, causing excessive stress concentration in weak areas of the impeller, leading to crack formation and propagation until fatigue fracture.

[0063] When a material or structure is subjected to repeated, varying loads, and the stress value never exceeds the material's strength limit, or is even lower than its elastic limit, failure may occur. This phenomenon of material or structural failure under continuous alternating loads is called fatigue failure.

[0064] In design and analysis, fatigue life analysis can be performed using the stress-life method, strain-life method, and linear elastic fracture mechanics analysis method. For example, the number of failure load cycles can be represented by N. 1 ≤ N ≤ 10⁵ cycles is called low-cycle fatigue, and N > 10⁵ cycles is called high-cycle fatigue.

[0065] In some embodiments, when calculating fatigue life based on the stress response analysis results, a fatigue point can be selected first, and the maximum and minimum alternating stresses of the fatigue point within the impeller analysis cycle can be extracted from the stress response analysis results. Then, a Goodman curve is generated based on the maximum and minimum alternating stresses. Following the stress correction principle, the position of the fatigue point on the Goodman curve is determined, and the fatigue life is calculated based on the position of the fatigue point on the Goodman curve.

[0066] For example, fatigue strength can be improved by changing the mean stress and alternating stress. Figure 7 As shown, Figure 7 The diagram illustrates various criteria for fatigue failure. For each criterion, a design point above a straight line or curve indicates material failure. For example, the material fails above fatigue point A on the Goodman curve.

[0067] In some embodiments, when calculating fatigue life based on the location of the fatigue point on the Goodman curve, the impeller material of the main pump impeller and the corresponding stress-life curve can be obtained first. Then, the stress amplitude is calculated based on the maximum alternating stress and the minimum alternating stress. The stress amplitude characterizes the difference between the maximum and minimum alternating stresses and the average stress, respectively. The stress amplitude is then corrected using the Goodman curve, and the number of cycles corresponding to the corrected stress amplitude is found on the stress-life curve to obtain the fatigue life.

[0068] For example, such as Figure 8 As shown, the maximum and minimum alternating stresses at these nodes selected through transient analysis are calculated over one impeller cycle, and a Goodman diagram is generated. Stress corrections are then applied to determine the location of each node on the Goodman diagram. Based on the stress-life method, and using the Goodman linear fatigue criterion, the fatigue life of the blade is calculated.

[0069] By applying the technical solutions of the above embodiments, the spatiotemporal domain conversion method for the flow field load of the shielded main pump impeller can perform fluid analysis and structural analysis using two different numerical analysis methods for the shielded main pump impeller. The fluid analysis can adopt the principle of rotating machinery fluid analysis, while the structural analysis adopts the principle of finite element analysis. Detailed analysis of impeller stress intensity and fatigue under water pulsation pressure is carried out, considering complex hydrodynamic loads and centrifugal loads. A complete fatigue life analysis process and evaluation system are established, forming a calculation method for the operational safety of the nuclear main pump impeller. This provides strong technical support and guarantee for the operational safety of shielded main pumps and subsequent pump products.

[0070] Furthermore, as a specific implementation of the spatiotemporal domain conversion method for the flow field load of the shielded main pump impeller described in the above embodiments, some embodiments of this application also provide a spatiotemporal domain conversion system for the flow field load of the shielded main pump impeller, such as... Figure 9 As shown, the system includes: The model building module is used to build the analysis model, which includes a three-dimensional water body model and an impeller structure model. The first calculation module is used to perform fluid dynamics analysis and calculation on the three-dimensional water body model to obtain unsteady flow field results, including blade surface pressure data. The conversion module is used to perform spatiotemporal domain conversion of the impeller flow field load based on the unsteady flow field results, so as to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model; The second calculation module is used to perform transient dynamic analysis on the impeller structure model under preset simulated load conditions based on the finite element analysis principle, so as to generate stress response analysis results. The simulated load includes hydrodynamic load and centrifugal load. The fatigue life output module calculates the fatigue life based on the stress response analysis results.

[0071] By applying the technical solutions of the above embodiments, the above embodiments provide a spatiotemporal conversion system for the flow field load of a shielded main pump impeller. After constructing a three-dimensional water body model and an impeller structure model, the system performs fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results. Then, based on the unsteady flow field results, it performs spatiotemporal conversion of the impeller flow field load, using point cloud technology to import and load the unsteady flow field results obtained from CFD analysis into the structural field, completing the transfer and application of the flow field load on the structural surface. Furthermore, it applies hydrodynamic and centrifugal loads through finite element analysis to perform stress response analysis on the main pump blades under transient conditions, realizing fatigue life calculation based on the stress response analysis results under unsteady conditions. The system analyzes with complex simulated loads and establishes a fatigue life analysis process and evaluation system, which can solve the problem of inaccurate loading of hydraulic loads on the main pump impeller.

[0072] It should be noted that other corresponding descriptions of the functional units involved in the spatiotemporal domain conversion system of the flow field load of the shielded main pump impeller provided in the embodiments of this application can be referred to the corresponding descriptions in the spatiotemporal domain conversion method of the flow field load of the shielded main pump impeller provided in the above embodiments, and will not be repeated here.

[0073] This application also provides a computer device, specifically a personal computer, server, network device, etc. The computer device includes a bus, processor, memory, and communication interface, and may also include input / output interfaces and a display device. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device stores location information. The network interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the steps in the various method embodiments.

[0074] Those skilled in the art will understand that the structure of the computer device described above is only a partial structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. A specific computer device may include more or fewer components, or combine certain components, or have different component arrangements.

[0075] In one embodiment, a computer-readable storage medium is also provided, which may be non-volatile or volatile, and a computer program is stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0076] In one embodiment, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0077] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0078] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods.

[0079] Any references to memory, database, or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc.

[0080] Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can take many forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0081] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchain. The processors involved in the embodiments provided in this application may be, but are not limited to, general-purpose processors, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for spatiotemporal conversion of flow field load on a shielded main pump impeller, characterized in that, The method includes: An analysis model is constructed, which includes a three-dimensional water body model and an impeller structure model; Fluid dynamics analysis and calculations are performed on the three-dimensional water body model to obtain unsteady flow field results, including blade surface pressure data. Based on the unsteady flow field results, perform a spatiotemporal transformation of the impeller flow field load to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model; Based on the principle of finite element analysis, transient dynamic analysis is performed on the impeller structure model under preset simulated load conditions to generate stress response analysis results. The simulated loads include hydrodynamic loads and centrifugal loads. The fatigue life is calculated based on the stress response analysis results.

2. The method according to claim 1, characterized in that, Build an analytical model, including: Obtain the two-dimensional structure diagram; A three-dimensional water body model is established based on the two-dimensional structure diagram, and a computational domain is created for the three-dimensional water body model to obtain a computational domain three-dimensional water body model. Based on the principles of computational fluid dynamics, the three-dimensional water body model of the computational domain is divided into fluid meshes.

3. The method according to claim 1, characterized in that, Perform fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results, including: Acquire calculation setting data, which includes one or more combinations of working medium data, calculation equation and turbulence model selection data, reference data, rotating domain data, inlet and outlet boundary condition data, convergence data, initial calculation field data, and output setting data; Set the calculation requirements information according to the calculation settings data; Obtain the number of blades of the main pump impeller and the current hardware configuration information, wherein the number of blades includes the number of moving blades and the number of stationary blades of the main pump impeller; The time step is determined according to the current hardware configuration information. The transient calculation of the flow field in the computational domain is performed based on the number of blades, the computational requirements, and the time step.

4. The method according to claim 3, characterized in that, Performing fluid dynamics analysis calculations on the three-dimensional water body model to obtain unsteady flow field results also includes: Obtain the results of transient calculations of the flow field in the computational domain; Select the target blade and static pressure setting in the main pump impeller, wherein the target blade is one of the multiple blades of the main pump impeller; The target blade's surface pressure data is output according to the static pressure settings. The blade surface pressure data includes node coordinates and static pressure values. The node coordinates are the coordinates of the fluid grid nodes arranged on the surface of the target blade. The static pressure values ​​are related to the node coordinates.

5. The method according to claim 1, characterized in that, Based on the unsteady flow field results, perform spatiotemporal transformation of the impeller flow field load, including: The load steps are set, including structural load steps and fluid load steps, and the structural load steps and the fluid load steps are kept consistent. Multiple structural field coordinates are selected, where the structural field coordinates are the position coordinates in the structural field corresponding to the fluid field coordinates of the impeller structural model; Based on the selected multiple structural field coordinates, coordinate transformation is performed on the pressure field structural data to obtain unsteady pulsating pressure data; The unsteady pulsating pressure data is projected onto the structural mesh of the impeller structure model.

6. The method according to claim 5, characterized in that, The method further includes: Develop spatiotemporal transformation rules for impeller flow field loads; Extract pressure data numbers, which are used to characterize the numbers corresponding to the fluid grids in the impeller flow field load; the pressure data numbers include start numbers and end numbers; Pressure data is extracted from the pressure field structure data based on the pressure data number; Determine the replication number, which is used to characterize the number corresponding to the structural mesh in the impeller structure model; Based on the spatiotemporal domain conversion rule of the impeller flow field load, the pressure data is imported into the structural mesh corresponding to the replication number.

7. The method according to claim 1, characterized in that, Based on the finite element analysis principle, transient dynamic analysis is performed on the impeller structure model under preset simulated load conditions to generate stress response analysis results, including: Define the input and output data for transient dynamic analysis. The input data is load data based on a time function. The output data is a time-varying derived quantity, which includes at least displacement data. The impeller rotation is divided into load steps, the same as in computational fluid dynamics analysis. Based on the input data and the simulated load, a transient dynamic stress response analysis is performed to obtain the impeller stress analysis results for the load step; According to the output data, stress data at key node locations are selected from the impeller stress analysis results. The stress data at key node locations are used to characterize the stress change over time during one revolution of the impeller. The key node locations are the node locations where the blade inlet and blade outlet intersect with the shaft disk and cover disk.

8. The method according to claim 1, characterized in that, The fatigue life is calculated based on the stress response analysis results, including: Select a fatigue point, and extract the maximum and minimum alternating stresses of the fatigue point within the impeller analysis cycle from the stress response analysis results; Goodman curves are generated based on the maximum alternating stress and the minimum alternating stress; Based on the stress correction principle, the position of the fatigue point in the Goodman curve is determined; Fatigue life is calculated based on the location of the fatigue point in the Goodman curve.

9. The method according to claim 8, characterized in that, Calculating fatigue life based on the location of the fatigue point on the Goodman curve includes: Obtain the impeller material of the main pump impeller and the stress-life curve corresponding to the impeller material; The stress amplitude is calculated based on the maximum alternating stress and the minimum alternating stress, and the stress amplitude is used to characterize the difference between the maximum alternating stress and the minimum alternating stress and the average stress, respectively. The stress amplitude is corrected using the Goodman curve. On the stress-life curve, find the number of cycles corresponding to the corrected stress amplitude to obtain the fatigue life.

10. A system for converting the spatiotemporal load of a shielded main pump impeller flow field, characterized in that, The system includes: The model building module is used to build the analysis model, which includes a three-dimensional water body model and an impeller structure model. The first calculation module is used to perform fluid dynamics analysis and calculation on the three-dimensional water body model to obtain unsteady flow field results, including blade surface pressure data. The conversion module is used to perform spatiotemporal domain conversion of the impeller flow field load based on the unsteady flow field results, so as to import the blade surface pressure data into the structural analysis domain corresponding to the impeller structure model; The second calculation module is used to perform transient dynamic analysis on the impeller structure model under preset simulated load conditions based on the finite element analysis principle, so as to generate stress response analysis results. The simulated load includes hydrodynamic load and centrifugal load. The fatigue life output module calculates the fatigue life based on the stress response analysis results.

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