Time step length determination method and device for solving physical quantity of transient physical process
By acquiring and updating time step iteration information, the predicted time step at the current moment can be quickly determined, which solves the problem of low efficiency in determining the time step in transient physics processes and achieves efficient physical quantity solving and accurate time step verification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA NUCLEAR POWER TECH RES INST CO LTD
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-10
AI Technical Summary
In transient physics processes, existing techniques struggle to efficiently determine the time step that allows physical quantities to converge, leading to longer solution times and reduced accuracy.
By acquiring the time step iteration information of historical moments in the transient physics process and the predicted time step of the previous moment, the predicted time step of the current moment is determined, and the convergence of the target physical quantity is achieved through iterative updates.
It can quickly and accurately determine the time step that makes physical quantities converge in transient physical processes, improving solution efficiency and accuracy, especially enhancing the computational efficiency of implicit solution algorithms.
Smart Images
Figure CN121835403A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of transient numerical solution technology, specifically to a method and apparatus for determining the time step of physical quantities in transient physical processes. Background Technology
[0002] In transient physics processes, the physical quantities involved change continuously over time. Taking the thermal-hydraulic process of a nuclear power plant as an example, the physical quantities involved may include fuel rod temperature, coolant flow rate, and pressure inside the reactor pressure vessel. To simulate the changes of physical quantities over time in transient physics processes, numerical methods can be used to solve for these physical quantities transiently.
[0003] In transient problem solving, the efficiency of determining the time step that brings physical quantities to converge directly determines the success or failure of the simulation: low efficiency not only significantly prolongs the solution time but may also affect the accuracy of the solution due to the inability to find a suitable time step in time. Currently, most methods determine the time step based on the rate of change of key physical quantities meeting certain conditions. However, the selection of key parameters and the measurement of convergence speed are quite complex, leading to poor efficiency in determining the time step that brings physical quantities to converge. Summary of the Invention
[0004] The main objective of this application is to propose a method and apparatus for determining the time step of physical quantities in transient physical processes, aiming to improve the efficiency of determining the time step that enables physical quantities to converge in transient physical processes.
[0005] This application provides a method for determining the time step for solving physical quantities in a transient physical process, comprising: acquiring first time step iteration information corresponding to a historical moment in the transient physical process; the first time step iteration information being used to characterize the iterative update of the time step during the process of solving the target physical quantity and the converged solution corresponding to the historical moment; the target physical quantity being the physical quantity to be solved in the transient physical process; determining the first predicted time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first predicted time step corresponding to the previous moment; iteratively updating the first predicted time step corresponding to the current moment to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current moment.
[0006] In one embodiment, determining the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment includes: determining a first time step scaling factor based on the first time step iteration information corresponding to the historical moment; and determining the first prediction time step corresponding to the current moment based on the first time step scaling factor and the first prediction time step corresponding to the previous moment.
[0007] In one embodiment, the number of target physical quantities is multiple; determining the first time step scaling factor based on the first time step iteration information corresponding to the historical time includes: for each target physical quantity, determining the second time step scaling factor corresponding to the historical time and the target physical quantity based on the first time step iteration information corresponding to the historical time and the target physical quantity; and determining the first time step scaling factor based on the second time step scaling factor corresponding to each target physical quantity for each historical time.
[0008] In one embodiment, the number of historical moments is multiple; determining the first time step scaling factor based on the first time step iteration information corresponding to the historical moment includes: for each historical moment, determining the third time step scaling factor corresponding to the historical moment based on the first time step iteration information corresponding to the historical moment; and determining the first time step scaling factor based on the third time step scaling factor corresponding to each historical moment.
[0009] In one embodiment, the step of iteratively updating the first predicted time step corresponding to the current time to obtain a target time step that makes the target physical quantity converge with the solution corresponding to the current time includes: using the transient differential equation corresponding to the target physical quantity, and based on the first predicted time step corresponding to the current time, iteratively solving the solution corresponding to the target physical quantity with the solution corresponding to the current time; during the iterative solution process, according to the convergence of the solution corresponding to the target physical quantity with the solution corresponding to the current time, iteratively updating the first predicted time step corresponding to the current time to obtain the target time step.
[0010] In one embodiment, the step of using the transient differential equation corresponding to the target physical quantity and iteratively solving the solution corresponding to the target physical quantity and the current time based on the first prediction time step corresponding to the current time includes: implicitly discretizing and transforming the transient differential equation to obtain the target equation corresponding to the target physical quantity; substituting the first prediction time step corresponding to the current time into the target equation and iteratively solving the solution corresponding to the target physical quantity and the current time.
[0011] In one embodiment, determining the first predicted time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first predicted time step corresponding to the previous moment includes: determining the second predicted time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first predicted time step corresponding to the previous moment; comparing the second predicted time step with a preset time step interval to obtain a comparison result; the preset time step interval is determined based on the intensity of the transient physical process; and determining the first predicted time step corresponding to the current moment based on the comparison result.
[0012] In one embodiment, after iteratively updating the first predicted time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time, the method further includes: obtaining second time step iteration information corresponding to the current time and the target physical quantity; the second time step iteration information is used to characterize the iterative update of the time step during the process of solving the converged solution corresponding to the target physical quantity and the current time; updating the first time step iteration information according to the second time step iteration information, and returning to the step of obtaining the first time step iteration information corresponding to the historical time during the transient physics process.
[0013] In one embodiment, obtaining the first time step iteration information corresponding to the historical moment in the transient physical process includes: for each historical moment, obtaining the target time step that makes the target physical quantity converge with the solution corresponding to the historical moment; In response to the fact that the sum of the target time steps corresponding to each of the historical moments is less than the preset observation duration of the transient physical process, the first time step iteration information corresponding to the historical moment is obtained.
[0014] This application embodiment also provides a time step determination device for solving physical quantities in a transient physical process, including an acquisition module, a determination module, and an update module; the acquisition module is used to acquire first time step iteration information corresponding to historical moments in the transient physical process; the first time step iteration information is used to characterize the iterative update of the time step during the process of solving the target physical quantity and the converged solution corresponding to the historical moment; the target physical quantity is the physical quantity to be solved in the transient physical process; the determination module is used to determine the first predicted time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first predicted time step corresponding to the previous moment; the update module is used to iteratively update the first predicted time step corresponding to the current moment to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current moment.
[0015] This application provides a method and apparatus for determining the time step for solving physical quantities in transient physical processes. Based on the iterative information of the first time step corresponding to a historical moment in the transient physical process and the first predicted time step corresponding to the previous moment, the method can quickly and accurately determine the first predicted time step corresponding to the current moment. Then, by iteratively updating the first predicted time step corresponding to the current moment, the method obtains the target time step that makes the target physical quantity converge with the solution corresponding to the current moment. This realizes the verification and adjustment of the first predicted time step corresponding to the current moment, thereby enabling the rapid determination of the time step that makes the physical quantity converge in the transient physical process. Attached Figure Description
[0016] Figure 1 This is a flowchart illustrating the time step determination method provided in the embodiments of this application.
[0017] Figure 2 This is a schematic diagram of the specific process of the time step determination method provided in the embodiments of this application.
[0018] Figure 3 This is a schematic diagram of the time step determination device provided in the embodiments of this application.
[0019] Figure 4 This is a schematic diagram of the structure of an embodiment of the electronic device provided in this application. Detailed Implementation
[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.
[0021] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0022] The time step determination method for solving physical quantities in transient physical processes provided in this application can be applied to electronic devices, which can be terminals or servers. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, etc.; the server can be configured as an independent physical server, or as a server cluster or distributed system composed of multiple physical servers, or as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the time step determination method provided in this application can also run in the software of the electronic device, and the software can be an application that implements the time step determination method, but is not limited to the above forms.
[0023] The method for determining the time step for solving physical quantities in transient physical processes, provided in this application, will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0024] Please see Figure 1 This application provides a method for determining the time step for solving physical quantities in a transient physical process, which may include, but is not limited to, the following steps: Step S101: Obtain the first time step iteration information corresponding to the historical moment in the transient physics process; the first time step iteration information is used to characterize the iterative update of the time step during the process of solving the target physical quantity and the converged solution corresponding to the historical moment; the target physical quantity is the physical quantity to be solved in the transient physics process; Optionally, the first time step iteration information may include at least one of the following: the number of iteration updates of the time step, and the adjustment range of the time step in each iteration update process.
[0025] In practical implementation, for each moment in the transient physical process, a predicted time step can be determined first. Then, numerical methods can be used to iteratively solve for the target physical quantity by updating this predicted time step until the solution for the target physical quantity converges, thus obtaining the target time step that makes the target physical quantity converge with the solution corresponding to that moment. During this process, the number of iterations of the time step update and / or the adjustment magnitude of the time step in each iteration update can be stored as the first time step iteration information corresponding to that moment.
[0026] Step S102: Determine the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment; It is understandable that, when the current moment is not the initial moment of the transient physical process, there exists a historical moment and a previous moment for the current moment. Optionally, the previous moment can be the historical moment that is closest to the current moment. Optionally, the first prediction time step corresponding to the initial moment of the transient physical process can be a preset value.
[0027] Optionally, the previous time and the current time can be two adjacent time points preset in the transient physics process; the current time can also be determined based on the sum of the target time steps corresponding to the previous time and the previous time; the target time step corresponding to the previous time can be understood as the target time step that makes the target physical quantity converge with the solution corresponding to the previous time.
[0028] In practice, the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment can be used to query the time step iteration information of the historical moment, the correspondence between the prediction time step of the previous moment and the prediction time step of the current moment, and obtain the first prediction time step corresponding to the current moment.
[0029] Alternatively, the first time step scaling factor can be determined first based on the first time step iteration information corresponding to the historical moment; then, the first prediction time step corresponding to the current moment can be determined based on the first time step scaling factor and the first prediction time step corresponding to the previous moment. For specific implementation details, please refer to the relevant description below, which will not be described here.
[0030] Step S103: Iteratively update the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time.
[0031] In practice, a numerical algorithm can be used to solve for the target physical quantity and the solution corresponding to the current time based on the first prediction time step corresponding to the current time. Then, in response to the non-convergence of the solution corresponding to the target physical quantity and the solution corresponding to the current time, the first prediction time step corresponding to the current time can be iteratively updated. Then, the first prediction time step corresponding to the current time can be updated to the latest first prediction time step, and the process of using the numerical algorithm to solve for the target physical quantity and the solution corresponding to the current time based on the first prediction time step corresponding to the current time can be returned to continue until the solution corresponding to the target physical quantity and the solution corresponding to the current time converges. Finally, the first prediction time step is determined as the target time step.
[0032] This application embodiment can quickly and accurately determine the first predicted time step corresponding to the current moment by using the iterative information of the first time step corresponding to the historical moment in the transient physical process and the first predicted time step corresponding to the previous moment. Then, by iteratively updating the first predicted time step corresponding to the current moment, the target time step that makes the target physical quantity converge with the solution corresponding to the current moment is obtained. This realizes the verification and adjustment of the first predicted time step corresponding to the current moment, thereby enabling the rapid determination of the time step that makes the physical quantity converge in the transient physical process.
[0033] In one embodiment, step S102 above: determining the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, includes: The first time step scaling factor is determined based on the first time step iteration information corresponding to the historical moment. The first prediction time step corresponding to the current time step is determined based on the first time step scaling factor and the first prediction time step corresponding to the previous time step.
[0034] In practice, the first time step iteration information corresponding to the historical moment can be input into the first neural network model to obtain the first time step scaling factor. The first neural network model can be a model that has learned the correspondence between the time step iteration information and the time step scaling factor. Alternatively, the first time step iteration information corresponding to the historical moment can be used to query a preset correspondence table between the time step iteration information and the time step scaling factor to obtain the first time step scaling factor.
[0035] In practice, the first time step scaling factor and the first predicted time step corresponding to the previous time step can be input into the first neural network model to obtain the first predicted time step corresponding to the current time step. The second neural network model can be a model that has learned the correspondence between the time step scaling factor, the predicted time step corresponding to the previous time step, and the predicted time step corresponding to the current time step. Alternatively, the first time step scaling factor and the first predicted time step corresponding to the previous time step can be used to query a preset correspondence table between the time step scaling factor, the predicted time step corresponding to the previous time step, and the predicted time step corresponding to the current time step to obtain the first predicted time step corresponding to the current time step.
[0036] Alternatively, the first prediction time step corresponding to the current moment can be determined using formula (1): (1) in, This indicates the first prediction time step corresponding to the current moment; This indicates the first prediction time step corresponding to the previous time step; Indicates the scaling factor for the first time step; These represent the first time step iteration information corresponding to each of the p+1 historical moments.
[0037] The embodiments of this application determine the first time step scaling factor based on the first time step iteration information corresponding to the historical moment; and based on the first time step scaling factor and the first predicted time step corresponding to the previous moment, the first predicted time step corresponding to the current moment can be quickly and accurately determined, thereby enabling the target time step that makes the target physical quantity converge with the solution corresponding to the current moment to be quickly determined based on the first predicted time step corresponding to the current moment.
[0038] Optionally, the number of the aforementioned target physical quantities is multiple. In one embodiment, determining the first time step scaling factor based on the first time step iteration information corresponding to historical moments includes: For each target physical quantity, the second time step scaling factor corresponding to the target physical quantity is determined based on the first time step iteration information corresponding to the historical time and the target physical quantity. The first time step scaling factor is determined based on the second time step scaling factor corresponding to each target physical quantity at each historical moment.
[0039] Optionally, when there are multiple target physical quantities, the first time step iteration information corresponding to the historical moment may include the number of iterations of the time step corresponding to the historical moment and each physical quantity, and the adjustment range of the time step in each iteration.
[0040] For each target physical quantity, the second time step scaling factor corresponding to the target physical quantity can be determined based on the first time step iteration information corresponding to the historical time and the target physical quantity. For the specific implementation method, please refer to the above implementation method of determining the first time step scaling factor based on the first time step iteration information corresponding to the historical time. It will not be repeated here.
[0041] Next, the second time step scaling factor corresponding to each target physical quantity at each historical moment can be input into the trained first scaling factor fitting model to obtain the first time step scaling factor; alternatively, the second time step scaling factor corresponding to each target physical quantity at each historical moment can be substituted into the first scaling factor fitting function to obtain the first time step scaling factor.
[0042] In this embodiment, for each target physical quantity, the first step is to determine the second time step scaling factor corresponding to the target physical quantity based on the first time step iteration information corresponding to the historical time and the target physical quantity. Then, based on the second time step scaling factor corresponding to each target physical quantity at each historical time, the first time step scaling factor is determined. This can improve the accuracy of determining the first time step scaling factor, thereby improving the accuracy of determining the first prediction time step corresponding to the current time using the first time step scaling factor.
[0043] Optionally, the number of historical moments can be multiple. In one embodiment, determining the first time step scaling factor based on the first time step iteration information corresponding to the historical moments includes: For each historical moment, the third time step scaling factor corresponding to the historical moment is determined based on the first time step iteration information corresponding to the historical moment. The first time step scaling factor is determined based on the third time step scaling factor corresponding to each historical moment.
[0044] Optionally, when there are multiple historical moments, the third time step scaling factor corresponding to each historical moment can be determined based on the first time step information corresponding to each historical moment. For the specific implementation method, please refer to the above implementation method of determining the first time step scaling factor based on the first time step iteration information corresponding to the historical moment, which will not be repeated here. Next, the third time step scaling factor corresponding to each historical moment can be input into the trained second scaling factor fitting model to obtain the first time step scaling factor; alternatively, the second time step scaling factor corresponding to each target physical quantity can be substituted into the second scaling factor fitting function to obtain the first time step scaling factor.
[0045] In this embodiment, for each historical moment, the third time step scaling factor corresponding to the historical moment is first determined based on the first time step iteration information corresponding to the historical moment; then, based on the third time step scaling factor corresponding to each historical moment, the first time step scaling factor is determined, which can improve the accuracy of determining the first time step scaling factor, thereby improving the accuracy of determining the first prediction time step corresponding to the current moment using the first time step scaling factor.
[0046] In one embodiment, determining the first time step scaling factor based on the first time step iteration information corresponding to historical moments includes: For each historical moment, based on the first time step iteration information corresponding to each target physical quantity at each historical moment, determine the second time step scaling factor corresponding to each target physical quantity at each historical moment; Based on the second time step scaling factor corresponding to each target physical quantity at each historical moment, the third time step scaling factor corresponding to the historical moment is determined. The first time step scaling factor is determined based on the third time step scaling factor corresponding to each historical moment.
[0047] In actual implementation, the scaling factor of the first time step can be determined using formulas (2) and (3): (2) (3) in, , ... This represents the first time step iteration information corresponding to the k+1 target physical quantities at the i-th historical moment; , ... This represents the second time step scaling factor corresponding to the k+1 target physical quantities at the i-th historical moment; This represents the scaling factor for the third time step corresponding to the i-th historical moment; n is a positive integer greater than p.
[0048] In this embodiment, for each historical moment, a second time step scaling factor corresponding to each target physical quantity is first determined based on the first time step iteration information corresponding to each historical moment and each target physical quantity. Then, based on the second time step scaling factor corresponding to each historical moment and each target physical quantity, a third time step scaling factor corresponding to the historical moment is determined. Finally, based on the third time step scaling factor corresponding to each historical moment, a first time step scaling factor is determined. This improves the accuracy of determining the first time step scaling factor, thereby improving the accuracy of determining the first prediction time step corresponding to the current moment using the first time step scaling factor.
[0049] In one embodiment, step S103 above: iteratively updating the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time, includes: Using the transient differential equation corresponding to the target physical quantity, and based on the first predicted time step corresponding to the current time, the solution corresponding to the target physical quantity and the current time is solved iteratively. During the iterative solution process, the first predicted time step corresponding to the current time is iteratively updated based on the convergence of the target physical quantity and the solution corresponding to the current time, so as to obtain the target time step.
[0050] Alternatively, the transient differential equation can be as shown in equation (4): (4) in, , Represents the generalized diffusion coefficient. Indicates a generalized source term. It represents a general variable that can represent the physical quantity to be solved in a transient physical process; This indicates the content of a physical quantity per unit volume; A quantity representing the amount of physical quantity passing through a unit area per unit time, perpendicular to the direction of flow velocity; Let be the gradient of a physical quantity, representing the maximum rate of change of the physical quantity in space and its direction; for different target physical quantities... and They can be different.
[0051] In practice, the transient differential equation corresponding to the target physical quantity can be discretized and converted into an equation related to the time step. Then, the first predicted time step corresponding to the current time can be input into the converted equation. By iteratively updating the first predicted time step corresponding to the current time, the solution corresponding to the target physical quantity and the current time can be solved iteratively. Until the solution corresponding to the target physical quantity and the current time converges, the latest first predicted time step is determined as the target time step.
[0052] This application embodiment utilizes the transient differential equation corresponding to the target physical quantity and iteratively solves the solution corresponding to the target physical quantity and the current time based on the first predicted time step corresponding to the current time. During the iterative solution process, the first predicted time step corresponding to the current time is iteratively updated according to the convergence of the solution corresponding to the target physical quantity and the current time to obtain the target time step, which can improve the efficiency of determining the target time step that makes the solution corresponding to the target physical quantity and the current time converge.
[0053] In one embodiment, the above-mentioned method of using the transient differential equation corresponding to the target physical quantity, and iteratively solving for the solution corresponding to the target physical quantity and the current time based on the first prediction time step corresponding to the current time, includes: Implicit discretization and nonlinear equation transformation are performed on the transient differential equation to obtain the target equation corresponding to the target physical quantity; Substitute the first prediction time step corresponding to the current moment into the objective equation, and iteratively solve for the objective physical quantity and the solution corresponding to the current moment.
[0054] In practice, the transient differential equations corresponding to the target physical quantity can be implicitly discretized first, and then the implicitly discretized equations can be converted into nonlinear equations to obtain the target equations corresponding to the target physical quantity. Next, the first prediction time step corresponding to the current moment can be substituted into the target equations, and the solutions corresponding to the target physical quantity and the current moment can be iteratively solved.
[0055] This application embodiment obtains the target equation corresponding to the target physical quantity by implicitly discretizing and transforming the transient differential equation; and by substituting the first predicted time step corresponding to the current time into the target equation, iteratively solving the target physical quantity and the solution corresponding to the current time, which can improve the efficiency and accuracy of solving the target physical quantity and the solution corresponding to the current time.
[0056] In one embodiment, step S102 above: determining the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, includes: Based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, determine the second prediction time step corresponding to the current moment; The second predicted time step is compared with the preset time step interval to obtain the comparison result; the preset time step interval is determined based on the severity of the transient physical process. Based on the comparison results, determine the first prediction time step corresponding to the current moment.
[0057] In practice, the time step interval can be preset based on the severity of the transient physical process. t min , t max Then, based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, the second prediction time step corresponding to the current moment can be determined; the specific implementation of this process can be referred to the relevant description in the above embodiments, which will not be repeated here.
[0058] Then, formula (5) can be used to compare the second prediction time step corresponding to the current time with the preset time step interval to obtain the first prediction time step corresponding to the current time: (5) in, This indicates the first prediction time step corresponding to the current moment; This indicates the second prediction time step corresponding to the current moment. If exist[ t min , t max Within the interval, then... Determined as ;like Not here tmin , t max Within the interval, and > t max Then you can t max Determined as ;like Not here t min , t max Within the interval, and < min Then you can t min Determined as .
[0059] This application embodiment determines the second predicted time step corresponding to the current moment by using the first time step iteration information corresponding to the historical moment and the first predicted time step corresponding to the previous moment; compares the second predicted time step with a preset time step interval to obtain a comparison result; the preset time step interval is determined based on the intensity of the transient physical process; and determines the first predicted time step corresponding to the current moment based on the comparison result, which can further improve the accuracy of predicting the time step corresponding to the current moment.
[0060] In one embodiment, after step S103 above: iteratively updating the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time, the time step determination method provided in this application embodiment further includes: Obtain the second time step iteration information corresponding to the target physical quantity at the current time; the second time step iteration information is used to characterize the iterative update of the time step during the process of solving the convergent solution corresponding to the target physical quantity at the current time. Based on the second time step iteration information, update the first time step iteration information, and return to the step of obtaining the first time step iteration information corresponding to the historical moment in the transient physics process.
[0061] Optionally, the second time step iteration information may include the number of iteration updates of the time step corresponding to the target physical quantity at the current time, and the adjustment range of the time step in each iteration update process.
[0062] In actual implementation, during the execution of step S103, the second time step iteration information corresponding to the target physical quantity at the current time can be stored. After obtaining the target time step that makes the solution corresponding to the target physical quantity at the current time converge, the second time step iteration information corresponding to the target physical quantity at the current time can be used as the first time step iteration information corresponding to the newly added historical time. Then, the execution can return to step S101 to obtain the first time step iteration information corresponding to the historical time in the transient physical process. By repeating this process, the target time step that makes the solution corresponding to the target physical quantity at each time converge in the transient physical process can be continuously determined.
[0063] This application embodiment improves the efficiency of determining the time step for physical quantities to converge during transient physics by obtaining the second time step iteration information corresponding to the target physical quantity at the current moment; updating the first time step iteration information based on the second time step iteration information; and returning to execute the steps of obtaining the first time step iteration information corresponding to the historical moment during the transient physics process.
[0064] In one embodiment, obtaining the first time step iteration information corresponding to the historical moment in the transient physics process in step S101 includes: For each historical moment, obtain the target time step that makes the target physical quantity converge with the solution corresponding to the historical moment; In response to the fact that the sum of the target time steps corresponding to each historical moment is less than the preset observation duration of the transient physical process, the first time step iteration information corresponding to the historical moment is obtained.
[0065] In actual implementation, when there is only one historical moment, the target time step that makes the solution corresponding to the target physical quantity and the historical moment converge can be directly compared with the preset observation time of the transient physical process. If the target time step is less than the preset observation time, the first time step iteration information corresponding to the historical moment in the transient physical process is obtained in step S101. If the target time step is greater than or equal to the preset observation time, the first time step iteration information corresponding to the historical moment in the transient physical process is not obtained in step S101.
[0066] When there are multiple historical moments, the sum of the target time steps corresponding to each historical moment can be calculated first. Then, the sum of the target time steps is compared with the preset observation duration of the transient physical process. If the sum of the target time steps is less than the preset observation duration, the first time step iteration information corresponding to the historical moment in the transient physical process is obtained in step S101. If the sum of the target time steps is greater than or equal to the preset observation duration, the first time step iteration information corresponding to the historical moment in the transient physical process is not obtained in step S101.
[0067] It is worth mentioning that when there are multiple target physical quantities, for each target physical quantity, the sum of the target time steps corresponding to each historical moment can be determined. Then, the minimum value of the sum of the target time steps corresponding to each target physical quantity can be compared with the preset observation duration. If the minimum value of the sum of the target time steps is less than the preset observation duration, the first time step iteration information corresponding to the historical moment in the transient physical process is obtained in step S101. If the minimum value of the sum of the target time steps is greater than or equal to the preset observation duration, the first time step iteration information corresponding to the historical moment in the transient physical process is not obtained in step S101.
[0068] This application embodiment obtains the target time step that makes the solution corresponding to the target physical quantity converge for each historical moment; and obtains the first time step iteration information corresponding to the historical moment in response to the sum of the target time steps corresponding to each historical moment being less than the preset observation time of the transient physical process. This ensures the necessity of determining the time step that makes the physical quantity converge in the transient physical process.
[0069] Please see Figure 2 In one specific embodiment, the time step determination method provided in this application may include, but is not limited to, the following steps: Step S201: Initialization; This step can set the time step threshold based on the severity of the transient physical process. t min , t max ; Step S202: Determine whether it is the first P-sequence calculation; the first P-sequence calculation can be understood as the process of iteratively solving the convergent solution of the target physical quantity corresponding to the start time of the transient physical process; If it is the first P sequence to be calculated, then execute step S203: set the time step dt to the initial time step; this step can assign a preset value dt to the prediction time step corresponding to the starting time. If it is not the first P-sequence calculation, then proceed to step S204: predict the time step dt of the new moment by fitting the relation based on the iteration information of the P calculation sequences; this step can predict the time step dt of the new moment by fitting the relation based on the iteration information of the time step of the historical sequence calculation; the historical sequence calculation can be understood as the process of iteratively solving the convergent solution of the target physical quantity corresponding to the historical moment of the transient physical process; Step S205: Determine whether the time step dt exceeds the time step setting threshold; this step can be used to determine the time step interval formed by the time step dt and the time step setting threshold. t min , t max Compare them to determine whether they exceed the time step interval; If the time step dt exceeds the time step interval, then execute step S206: update the time step dt according to the threshold. If the time step dt does not exceed the time step interval, then step S207 can be executed: calculation of the transient differential equation at time t+dt; this step can use the transient differential equation to iteratively update the time step dt and solve for the target physical quantity; optionally, the transient differential equation can also be called the transient analysis equation; Step S208: Determine whether the calculation results of the transient differential equation have converged; this step can determine whether the solution of the target physical quantity has converged based on the residual of the transient differential equation. If the solution of the target physical quantity converges, then step S209 can be executed: memorize the iteration information within the time step dt and update the P sequence iteration information; this step can store the number of iteration updates of the time step dt and / or the adjustment magnitude of the time step dt during each iteration update as the first time step iteration information. If the solution for the target physical quantity does not converge, then step S210 can be executed: reduce the time step dt, and return to execute step S205. If the solution for the target physical quantity converges, then step S211 can be executed: determine whether T is less than T. max T can represent the sum of the target time steps obtained from P computational sequences. max It can represent the preset observation duration of a transient physical process; If T < T max Then return to step S202; If T≥T max If so, the process ends.
[0070] The specific implementation process of this embodiment can be found in the relevant descriptions in the above embodiments, and will not be repeated here.
[0071] The time step determination method provided in this application does not require the selection of key physical quantities or reliance on the rate of change of physical quantities. Based on the first time step iteration information corresponding to historical moments and the first predicted time step corresponding to the transient physical process at the previous moment, the first predicted time step corresponding to the current moment can be quickly and accurately determined. Then, by iteratively updating the first predicted time step corresponding to the current moment, the target time step that makes the solution corresponding to the target physical quantity converge with the solution corresponding to the current moment can be quickly determined. This method can better balance the efficiency and accuracy of solving the target physical quantity, and can achieve efficient transient analysis of transient physical processes. In particular, it can improve the computational efficiency of transient differential equations using implicit solution algorithms.
[0072] Please see Figure 3 This application also provides a time step determination device 300 for solving physical quantities of transient physical processes, including an acquisition module 301, a determination module 302 and an update module 303.
[0073] The acquisition module 301 is used to acquire the first time step iteration information corresponding to the historical moment in the transient physical process; the first time step iteration information is used to characterize the iterative update of the time step during the process of solving the target physical quantity and the converged solution corresponding to the historical moment; the target physical quantity is the physical quantity to be solved in the transient physical process. The determining module 302 is used to determine the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment. The update module 303 is used to iteratively update the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time.
[0074] The time step determination device for solving physical quantities of transient physical processes provided in this application embodiment can implement all the steps of the above-described time step determination method embodiment and achieve the same technical effect. To avoid repetition, it will not be described again here.
[0075] Optionally, embodiments of this application also provide an electronic device, including a processor and a memory. The memory stores a program or instructions that can run on the processor. When the program or instructions are executed by the processor, they implement the various steps of the above-described time step determination method embodiments and achieve the same technical effect. To avoid repetition, they will not be described again here. It should be noted that the electronic device in the embodiments of this application includes the above-described mobile electronic device and non-mobile electronic device.
[0076] Figure 4 To implement the hardware structure diagram of the electronic device in the embodiments of this application, the electronic device may include: The processor 401 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 402 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 402 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 402, and the processor 401 calls and executes the time step determination method of the embodiments of this application. Input / output interface 403 is used to implement information input and output; The communication interface 404 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 405 transmits information between various components of the device (e.g., processor 401, memory 402, input / output interface 403, and communication interface 404); The processor 401, memory 402, input / output interface 403 and communication interface 404 are connected to each other within the device via bus 405.
[0077] The electronic device provided in this application embodiment can implement all the steps of the above-described time step determination method embodiment and achieve the same technical effect. To avoid repetition, it will not be described again here.
[0078] This application also provides a computer-readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various steps of the above-described time step determination method embodiment and achieve the same technical effect. To avoid repetition, they will not be described again here.
[0079] The processor is the processor in the electronic device described in the above embodiments. The computer-readable storage medium includes computer-readable storage media such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.
[0080] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run programs or instructions to implement the various steps of the above-described time step determination method embodiments and can achieve the same technical effect. To avoid repetition, it will not be described again here.
[0081] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.
[0082] This application provides a computer program product, which is stored in a storage medium and executed by at least one processor to implement the various steps of the time step determination method embodiment described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.
[0083] It should be noted that, in this document, 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 limitations, 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 that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.
[0084] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.
[0085] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.
Claims
1. A method for determining the time step in solving physical quantities of a transient physical process, characterized in that, include: Obtain the first time step iteration information corresponding to the historical moment in the transient physics process; The first time step iteration information is used to characterize the iterative update of the time step during the process of solving the convergent solution corresponding to the target physical quantity and the historical time; the target physical quantity is the physical quantity to be solved in the transient physical process; Based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, determine the first prediction time step corresponding to the current moment; The first prediction time step corresponding to the current time is iteratively updated to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time.
2. The time step determination method as described in claim 1, characterized in that, The step of determining the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment includes: The first time step scaling factor is determined based on the first time step iteration information corresponding to the historical moment. The first prediction time step corresponding to the current moment is determined based on the first time step scaling factor and the first prediction time step corresponding to the previous moment.
3. The time step determination method as described in claim 2, characterized in that, The number of the target physical quantities is multiple; The step of determining the first time step scaling factor based on the first time step iteration information corresponding to the historical moment includes: For each target physical quantity, a second time step scaling factor is determined based on the first time step iteration information corresponding to the historical time and the target physical quantity. The first time step scaling factor is determined based on the second time step scaling factor corresponding to each of the target physical quantities at the historical moments.
4. The time step determination method as described in claim 2, characterized in that, The number of historical moments mentioned is multiple; The step of determining the first time step scaling factor based on the first time step iteration information corresponding to the historical moment includes: For each historical moment, a third time step scaling factor is determined based on the first time step iteration information corresponding to the historical moment. The first time step scaling factor is determined based on the third time step scaling factor corresponding to each of the historical moments.
5. The time step determination method as described in claim 1, characterized in that, The iterative update of the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time includes: Using the transient differential equation corresponding to the target physical quantity, and based on the first predicted time step corresponding to the current time, the solution corresponding to the target physical quantity and the current time is solved iteratively. During the iterative solution process, the first predicted time step corresponding to the current time is iteratively updated based on the convergence of the target physical quantity and the solution corresponding to the current time, so as to obtain the target time step.
6. The time step determination method as described in claim 5, characterized in that, The step of iteratively solving for the target physical quantity and the solution corresponding to the current time using the transient differential equation corresponding to the target physical quantity and based on the first prediction time step corresponding to the current time includes: The transient differential equation is implicitly discretized and nonlinearly transformed to obtain the target equation corresponding to the target physical quantity. Substitute the first prediction time step corresponding to the current moment into the objective equation, and iteratively solve for the objective physical quantity and the solution corresponding to the current moment.
7. The time step determination method as described in claim 1, characterized in that, The step of determining the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment includes: Based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment, the second prediction time step corresponding to the current moment is determined. The second predicted time step is compared with a preset time step interval to obtain a comparison result; the preset time step interval is determined based on the severity of the transient physical process. Based on the comparison results, the first prediction time step corresponding to the current moment is determined.
8. The time step determination method as described in claim 1, characterized in that, After iteratively updating the first prediction time step corresponding to the current time to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current time, the method further includes: Obtain the second time step iteration information corresponding to the target physical quantity at the current time; the second time step iteration information is used to characterize the iterative update of the time step during the process of solving the convergent solution corresponding to the target physical quantity at the current time; Based on the second time step iteration information, update the first time step iteration information, and return to the step of obtaining the first time step iteration information corresponding to the historical moment in the transient physics process.
9. The time step determination method as described in claim 1, characterized in that, The acquisition of the first time step iteration information corresponding to the historical moment in the transient physics process includes: For each historical moment, obtain the target time step that makes the target physical quantity converge with the solution corresponding to the historical moment; In response to the fact that the sum of the target time steps corresponding to each of the historical moments is less than the preset observation duration of the transient physical process, the first time step iteration information corresponding to the historical moment is obtained.
10. A device for determining the time step of physical quantities in a transient physical process, characterized in that, This includes an acquisition module, a determination module, and an update module; The acquisition module is used to acquire the first time step iteration information corresponding to the historical moment in the transient physics process; the first time step iteration information is used to characterize the iterative update of the time step during the process of solving the target physical quantity and the converged solution corresponding to the historical moment; the target physical quantity is the physical quantity to be solved in the transient physics process; The determining module is used to determine the first prediction time step corresponding to the current moment based on the first time step iteration information corresponding to the historical moment and the first prediction time step corresponding to the previous moment. The update module is used to iteratively update the first prediction time step corresponding to the current moment to obtain the target time step that makes the target physical quantity converge with the solution corresponding to the current moment.