A multi-physical field coupling calculation method and device based on a COMSOL platform
By combining the OpenMC program on the COMSOL platform, a multiphysics coupling calculation model and data transfer interface were established, which solved the defects in the calculation of neutron physics fields in reactor cores, realized transient nuclear thermodynamic coupling analysis of reactor cores, and captured the accurate characteristics under transient operating conditions.
Patent Information
- Application Number
- CN202510028631.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-08
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2045-01-08
AI Technical Summary
Existing multiphysics coupling analysis platforms cannot cover the calculation of neutron physics fields in reactor cores, resulting in the inability to fully obtain the coupling feedback effects of reactor cores under instantaneous operating conditions.
By combining the COMSOL platform with the OpenMC program, and establishing a multiphysics calculation model and data transfer interface, the neutron Monte Carlo calculation model and the point reactor dynamics model are coupled to capture the transient characteristics of the reactor core.
It realizes transient nuclear thermodynamic coupling calculation of reactor core system, and captures the accurate characteristics of corresponding geometric models and materials under transient conditions in real time, making up for the deficiency of COMSOL platform in being unable to perform neutron physics calculations.
Smart Images
Figure CN119962181B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of reactor coupling performance analysis, and particularly relates to a multi-physical field coupling calculation method and device based on a COMSOL platform. BACKGROUND
[0002] A reactor core is a multi-physical field coupling system, which involves multiple physical fields such as neutron physics, heat conduction and solid mechanics, and there is a strong coupling effect between the physical fields, which puts forward new requirements for numerical simulation tools from two aspects of local accuracy and overall description. Traditional single-tool numerical simulation often depends on assumed boundary conditions, so that the calculation results have certain limitations and conservatism, and therefore multi-physical coupling becomes an essential condition for high-fidelity numerical simulation of a reactor.
[0003] The COMSOL platform is a high-energy multi-physical field coupling program, which is based on the finite element method, solves partial differential equations (groups) to solve single physical fields or multi-physical fields, and covers multiple physical fields such as heat transfer, fluid flow, structural mechanics, electromagnetism and chemistry. Meanwhile, the COMSOL platform also provides a series of predefined physical interfaces and solvers, allowing users to model and solve problems in different fields, and through coupling of related physical interfaces, users can accurately capture the coupling effect and understand the overall behavior of the system.
[0004] The existing multi-physical field coupling analysis platform cannot cover the main physical fields existing in the reactor core, and most platforms lack the function of calculating the neutron physical field in the core, which makes the coupling platform unable to obtain the coupling feedback effect of the reactor core under transient conditions. In order to make the COMSOL platform obtain the coupling feedback effect of the reactor core under transient conditions, it is necessary to use the data transmission interface of the COMSOL platform and external software to expand the calculation range of the physical field, including using the neutron Monte Carlo calculation model and the point reactor dynamics model to calculate the steady-state neutron physical field characteristics and the transient reactor core power change respectively, so as to capture the accurate characteristics of the corresponding geometric model and material, and provide reference value for the safe design and operation of the reactor. SUMMARY
[0005] The application aims to provide a multi-physical field coupling calculation method and device based on a COMSOL platform, which can be used for nuclear-thermal coupling analysis of a reactor core fuel system, fully considers the coupling effect of multiple physical fields such as heat transfer, solid mechanics and neutron physics, and captures the accurate characteristics of the corresponding geometric model and material, thereby providing reference value for the safe design and operation of the reactor.
[0006] The application is implemented by using the following technical scheme: a multi-physical field coupling calculation method based on a COMSOL platform, comprising the following steps:
[0007] Step 1: Establish different physical field calculation models; including: establishing heat transfer, solid mechanics calculation models in COMSOL platform; using COMSOL platform mathematical module to solve point reactor dynamics model; establishing neutron Monte Carlo calculation model through OpenMC program input card;
[0008] Step 2: Develop data transmission interface; the data transmission interface includes heat transfer data interface, mechanics data interface and neutron data interface;
[0009] Step 3: Develop convergence criterion of coupling program; including: extracting the maximum stress of fuel calculated in each cycle as the convergence criterion of COMSOL platform operation; extracting the effective multiplication factor, a neutron physics parameter calculated in each cycle, as the convergence criterion of OpenMC program;
[0010] Step 4: COMSOL operation; including: at t0 time, using the initial assumed fuel heat source power density distribution in COMSOL platform to perform three-dimensional thermal expansion calculation, to obtain the temperature field and displacement field of the reactor core; wherein, t0 is the initial time;
[0011] Step 5: Heat transfer and mechanics data transmission; the heat transfer data interface extracts the average temperature of each sub-region of the reactor core fuel and transmits it to the input card of the OpenMC program to update the region temperature in the neutron physics model; the mechanics data interface extracts the thermal expansion displacement data of the fuel outer surface and transmits it to the input card of the OpenMC program after processing to update the geometry model and material properties in the neutron physics model;
[0012] Step 6: OpenMC operation, including: running the OpenMC program after data update, performing neutron Monte Carlo calculation, realizing the feedback of the thermal expansion effect of the reactor core on the neutron physics field;
[0013] Step 7: Convergence criterion judgment; if the coupling program has converged, continue the calculation of the next time step; if the coupling program has not converged, update the heat source distribution of the heat transfer physical field in the COMSOL platform through the neutron data interface, continue the coupling calculation of the current time step, and then perform the calculation of the next time step after the coupling program converges.
[0014] A multi-physical field coupling calculation device based on COMSOL platform, comprising the following modules:
[0015] The calculation model establishment module establishes heat transfer, solid mechanics calculation models in COMSOL platform; uses COMSOL platform mathematical module to solve point reactor dynamics model; establishes neutron Monte Carlo calculation model through OpenMC program input card;
[0016] The data transfer interface development module comprises a heat transfer data interface, a mechanical data interface and a neutron data interface;
[0017] The convergence criterion development module extracts the maximum stress of the fuel obtained in each cycle calculation as the convergence criterion of the COMSOL platform operation, and extracts the effective multiplication factor, a neutron physics parameter, obtained in each cycle calculation as the convergence criterion of the OpenMC program.
[0018] The COMSOL operation module performs three-dimensional thermal and mechanical expansion calculation on the COMSOL platform at t0, obtains the temperature field and displacement field of the reactor core, and adopts the initial assumed fuel heat source power density distribution; wherein t0 is the initial time.
[0019] The heat transfer and mechanical data transfer module extracts the average temperature of each sub-region of the reactor core fuel through the heat transfer data interface, and then transfers the average temperature to the input card of the OpenMC program to update the region temperature in the neutron physics model; the mechanical data interface extracts the thermal expansion displacement data of the outer surface of the fuel, and then transfers the thermal expansion displacement data to the input card of the OpenMC program after processing to update the geometric model and material properties in the neutron physics model.
[0020] The OpenMC operation module runs the OpenMC program after data update, performs neutron Monte Carlo calculation, and realizes the feedback of the influence of the thermal expansion effect of the reactor core on the neutron physics field.
[0021] The convergence criterion judgment module continues the calculation of the next time step if the coupling program has converged, and continues the coupling calculation of the current time step by updating the heat source distribution of the heat transfer physical field in the COMSOL platform through the neutron data interface if the coupling program has not converged, and then performs the calculation of the next time step after the coupling program converges.
[0022] An electronic device comprises a memory, a processor and a computer program stored on the memory and executable on the processor, and the processor implements the steps of the COMSOL platform-based multi-physical field coupling calculation method when executing the program.
[0023] A non-transitory computer readable storage medium has a computer program stored thereon, and the computer program implements the steps of the COMSOL platform-based multi-physical field coupling calculation method when executed by a processor.
[0024] The present application has the following beneficial effects:
[0025] This invention discloses a multiphysics coupling calculation method and apparatus based on the COMSOL platform. It couples a neutron Monte Carlo computational model and a point reactor dynamics model to the COMSOL platform. The point reactor dynamics model is used to calculate the transient changes in the overall core power, while the neutron Monte Carlo computational model uses the OpenMC program to update the spatial distribution of core power within each time step. This multiphysics coupling calculation method can perform transient nuclear thermodynamic coupling calculations of reactor core systems, capturing the precise characteristics of the corresponding geometric models and materials under transient conditions in real time. This invention realizes a multiphysics coupling calculation process based on the COMSOL platform, innovatively coupling neutron physics into the COMSOL platform, thus overcoming the original COMSOL platform's inability to perform neutron physics calculations. Attached Figure Description
[0026] Figure 1 This invention provides transient operating condition calculation steps for a multiphysics coupling calculation method based on the COMSOL platform. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0029] This invention provides a multiphysics coupling calculation method based on the COMSOL platform for the nuclear thermodynamic coupling analysis of reactor core fuel systems. Figure 1 The reactor core system was analyzed using the following process, and the following technical solutions were implemented:
[0030] Step 1: Establish three-dimensional geometric models of the reactor core under different physical fields. The geometric models for heat transfer and solid mechanics are built in the COMSOL platform. The correlation coefficients of the ordinary differential equations for the point reactor dynamics model are directly written into the COMSOL mathematical module. The geometric model for the neutron physics field is completed using the input card of the OpenMC program, an open-source software specifically designed for reactor neutron Monte Carlo calculations. Step 1 specifically includes:
[0031] 1.1 A three-dimensional heat transfer and solid mechanics calculation model is established in the COMSOL platform. This model includes:
[0032] (a) Establish the three-dimensional geometric model of the reactor core fuel system by the geometric modeling part;
[0033] (b) Mesh the geometric model and select the adaptive mesh for model calculation by the mesh independence verification;
[0034] (c) Create the corresponding material properties and perform the region selection;
[0035] (d) Complete the region selection and boundary condition setting of the physical fields such as heat transfer and solid mechanics.
[0036] 1.2 Solve the point reactor kinetics model using the mathematical module of the COMSOL platform, which includes:
[0037] (a) Calculate the point reactor neutronics parameters and core material feedback coefficients of the reactor core by the OpenMC program, including the delayed neutron fraction, decay time and neutron generation time; the core material feedback coefficients include the fuel feedback coefficient, Doppler feedback coefficient and thermal expansion feedback coefficient;
[0038] (b) Write the equation coefficients in the point reactor kinetics model into the mathematical module of the COMSOL platform;
[0039] (c) Complete the setting of the initial conditions of the equations of the point reactor kinetics model.
[0040] 1.3 Establish the neutron Monte Carlo calculation model by the input card of the OpenMC program, which includes:
[0041] (a) Geometry creation: define the physical space by the entity geometry CSG method;
[0042] (b) Material definition: specify the material composition elements and their relative abundance;
[0043] (c) Simulation settings: define the characteristics of the neutron source and the simulation type;
[0044] (d) Counting settings: collect physical quantities such as particle flux density.
[0045] Step 2: Develop the data transmission interface between the coupled programs, which includes:
[0046] 2.1 Heat transfer data interface: extract the average temperature of each sub-region of the reactor core fuel and transmit it to the OpenMC program input card, update the region temperature in the neutron physics model; extract the average temperature of the reactor core fuel at each transient time step as the reactivity feedback input in the point reactor kinetics model;
[0047] 2.2 Mechanical data interface: extract the thermal expansion displacement data of fuel geometry surface, and the data is transmitted to the input card of OpenMC program after processing, updating the geometry model and material properties in the neutron Monte Carlo calculation model;
[0048] 2.3 Neutronics data interface: extract the neutron flux density data in the fuel sub-region, and the data is transmitted to the heat transfer module of COMSOL platform after processing, updating the heat source distribution data in the heat transfer physical field.
[0049] Among them, the coupling program is a program coupling COMSOL platform and OpenMC program.
[0050] Step 3: Develop the convergence criterion of the coupling program, which specifically includes:
[0051] 3.1 Extract the maximum stress of fuel calculated in each cycle as the convergence criterion for the operation of COMSOL platform;
[0052] 3.2 Extract the neutronics physical parameters: effective multiplication factor calculated in each cycle as the convergence criterion for OpenMC program.
[0053] The convergence criterion is used to judge whether the program has reached convergence when the coupling program runs the calculation, if it reaches convergence, it stops the current time step and performs the calculation of the next time step, if it does not converge, it continues the calculation of the current time step.
[0054] Step 4: At time t0, use the initial assumed fuel heat source power density distribution to perform three-dimensional thermal and mechanical expansion calculation in COMSOL platform to obtain the temperature field and displacement field of the reactor core; wherein t0 is the initial time.
[0055] Step 5: The heat transfer data interface extracts the average temperature of each sub-region of the reactor core fuel and transmits it to the OpenMC program input card to update the region temperature in the neutron physics model; the mechanical data interface extracts the thermal expansion displacement data of the outer surface of the fuel, which is transmitted to the input card of OpenMC program after processing, updating the geometry model and material properties in the neutron physics model.
[0056] Step 6: Run the updated OpenMC program for neutron physics calculation, thereby realizing the feedback of the thermal expansion effect of the reactor core on the neutron physical field.
[0057] Step 7: whether the coupling program converges is judged by using a convergence criterion, if the coupling program has converged, the current time step calculation is directly terminated and the calculation of the next time step t0+dt is performed, if the coupling program has not converged, the neutron flux density of the fuel subregion is extracted by the neutron data interface, after processing, the neutron flux density is transmitted to the heat transfer module of the COMSOL platform, the heat source distribution data in the heat transfer physical field is updated, steps 4, 5 and 6 are re-executed, and after convergence, the calculation of the next time step is performed. Wherein, dt is the time increment from the initial time t0 to the next time step.
[0058] The coupling platform of the application can perform transient nuclear thermal force coupling calculation of the reactor core system, and accurately capture the precise characteristics of the corresponding geometric model and material under transient working conditions in real time. The method of the application establishes a multi-physical field calculation model of heat transfer, solid mechanics and neutron physics, and a data transmission interface thereof, wherein the neutron physics includes point reactor dynamics, realizes data mapping and transmission between different physical fields, and realizes the multi-physical field coupling calculation process based on the COMSOL platform. The application innovatively couples the neutron physics field into the COMSOL platform, which makes up for the defect that the original COMSOL platform cannot perform neutron physics calculation.
Claims
1. A multiphysics coupling calculation method based on the COMSOL platform, characterized in that, Includes the following steps: Step 1: Establish calculation models for different physical fields; including: establishing heat transfer and solid mechanics calculation models in the COMSOL platform; solving the point pile dynamics model using the mathematical module of the COMSOL platform; and establishing a neutron Monte Carlo calculation model through the input card of the OpenMC program. Step 2: Develop data transfer interfaces; the data transfer interfaces include heat transfer data interfaces, mechanical data interfaces, and neutronics data interfaces; Step 3: Develop convergence criteria for the coupled program; including: extracting the maximum fuel stress calculated in each loop as the convergence criterion for running on the COMSOL platform; extracting the effective multiplication factor, a neutron physics parameter calculated in each loop, as the convergence criterion for the OpenMC program; Step 4: COMSOL operation; including: at time t0, using the initial assumed fuel heat source power density distribution, performing three-dimensional thermodynamic expansion calculations on the COMSOL platform to obtain the temperature field and displacement field of the reactor core; where t0 is the initial time. Step 5: Heat and mechanical data transfer; The heat transfer data interface extracts the average temperature of each sub-region of the reactor core fuel and transfers it to the input card of the OpenMC program to update the region temperature in the neutron physics model; The average temperature of the reactor core fuel at each transient time step is extracted as the reactivity feedback input in the point reactor dynamics model; The mechanical data interface extracts the thermal expansion displacement data of the fuel outer surface, processes it, and transfers it to the input card of the OpenMC program to update the geometric model and material properties in the neutron physics model; The neutron flux density data of the fuel sub-region is extracted by the neutron data interface, and the data is processed and transferred to the heat transfer module of the COMSOL platform to update the heat source distribution data in the heat transfer physics field; Step 6: Run OpenMC, including: running the updated OpenMC program, performing neutron Monte Carlo calculations, and realizing the feedback of the impact of the thermal expansion effect of the reactor core on the neutron physics field; Step 7: Convergence Criterion Judgment; If the coupling program has converged, continue the calculation for the next time step; if the coupling program has not converged, update the heat source distribution of the heat transfer physics field in the COMSOL platform through the neutronics data interface, continue the coupling calculation for the current time step, and proceed to the calculation for the next time step after the coupling program converges; use the convergence criterion to determine whether the coupling program has converged. If it has converged, directly terminate the calculation for the current time step and proceed to the calculation for the next time step t0+dt; if it has not converged, extract the neutron flux density of the fuel sub-region through the neutronics data interface, process it, and transmit it to the heat transfer module of the COMSOL platform to update the heat source distribution data of the heat transfer physics field, and re-execute steps 4, 5, and 6, and proceed to the calculation for the next time step after convergence; where dt is the time increment from the initial time t0 to the next time step.
2. The multiphysics coupling calculation method based on the COMSOL platform according to claim 1, characterized in that, Step 1, specifically establishing the heat transfer and solid mechanics calculation model in the COMSOL platform, includes: establishing a three-dimensional geometric model of the reactor core fuel system through the geometric modeling part of the COMSOL platform; meshing the geometric model and selecting the appropriate mesh for model calculation through mesh independence verification; creating corresponding material properties and selecting regions; and completing the region selection and boundary conditions required for setting the heat transfer and solid mechanics physical fields.
3. The multiphysics coupling calculation method based on the COMSOL platform according to claim 1, characterized in that, In step 1, the specific steps of solving the point reactor dynamics model using the mathematical module of the COMSOL platform include: calculating the point reactor neutronics parameters and core material feedback coefficients required for the point reactor dynamics model using the OpenMC program; writing the equation coefficients in the point reactor dynamics model into the mathematical module of the COMSOL platform; and setting the initial conditions for the equations of the point reactor dynamics model.
4. The multiphysics coupling calculation method based on the COMSOL platform according to claim 3, characterized in that, The point pile neutronics parameters include the delayed neutron fraction, decay time, and neutron generation time.
5. The multiphysics coupling calculation method based on the COMSOL platform according to claim 3, characterized in that, The core material feedback coefficients include the fuel feedback coefficient, the Doppler feedback coefficient, and the thermal expansion feedback coefficient.
6. The multiphysics coupling calculation method based on the COMSOL platform according to claim 1, characterized in that, In step 1, establishing the neutron Monte Carlo computation model through the input card of the OpenMC program specifically includes: configuring the input card of the OpenMC program and completing geometry creation, material definition, simulation settings, and counting settings; wherein, completing geometry creation includes constructing solid geometry and defining the physical space using the CSG method, material definition includes specifying the constituent elements of the material and their relative abundance, simulation settings include defining the neutron source characteristics and simulation type, and counting settings include collecting particle flux density.
7. The multiphysics coupling calculation method based on the COMSOL platform according to claim 1, characterized in that, In step 2, The heat transfer data interface is used to extract the average temperature of each sub-region of the reactor core fuel and transmit it to the OpenMC program input card to update the region temperature in the neutron physics model; it also extracts the average temperature of the reactor core fuel at each transient time step as the reactivity feedback input in the point reactor dynamics model. The mechanical data interface is used to extract thermal expansion displacement data of the outer geometric surface of the fuel. After processing, the data is transmitted to the input card of the OpenMC program to update the geometric model and material properties in the neutron Monte Carlo calculation model. The neutronics data interface is used to extract neutron flux density data of the fuel sub-region. After processing, the data is transmitted to the heat transfer module of the COMSOL platform to update the heat source distribution data in the heat transfer physics field.
8. A multiphysics coupling computing device based on the COMSOL platform, characterized in that, Includes the following modules: The computational model building module establishes heat transfer and solid mechanics computational models in the COMSOL platform; it solves the point pile dynamics model using the mathematical module of the COMSOL platform; and it establishes a neutron Monte Carlo computational model through the input card of the OpenMC program. The data transfer interface development module includes the development of heat transfer data interfaces, mechanical data interfaces, and neutronics data interfaces. The convergence criterion development module extracts the maximum fuel stress calculated in each loop and uses it as the convergence criterion for running on the COMSOL platform. The effective multiplication factor, a neutron physics parameter obtained from each loop calculation, is extracted and used as the convergence criterion for the OpenMC program. The COMSOL operating module performs three-dimensional thermodynamic expansion calculations on the COMSOL platform at time t0, using the initial assumption of the fuel heat source power density distribution, to obtain the temperature field and displacement field of the reactor core; where t0 is the initial time. The heat transfer and mechanical data transfer module extracts the average temperature of each sub-region of the reactor core fuel from the heat transfer data interface and transfers it to the input card of the OpenMC program to update the region temperature in the neutron physics model; it also extracts the average temperature of the reactor core fuel at each transient time step as the reactivity feedback input in the point reactor dynamics model; the mechanical data interface extracts the thermal expansion displacement data of the fuel outer surface, processes it, and transfers it to the input card of the OpenMC program to update the geometric model and material properties in the neutron physics model; the neutron flux density data of the fuel sub-regions is extracted from the neutron data interface, processed, and then transferred to the heat transfer module of the COMSOL platform to update the heat source distribution data in the heat transfer physics field. The OpenMC runtime module runs the updated OpenMC program to perform neutron Monte Carlo calculations, realizing the feedback of the impact of the thermal expansion effect of the reactor core on the neutron physics field. The convergence criterion module determines whether the coupling program has converged. If it has, the calculation continues to the next time step. If it has not converged, the heat source distribution of the heat transfer physics field in the COMSOL platform is updated through the neutronics data interface, and the coupling calculation for the current time step continues until the coupling program converges before proceeding to the next time step. The convergence criterion is used to determine whether the coupling program has converged. If it has, the calculation for the current time step is terminated and the calculation proceeds to the next time step t0+dt. If it has not converged, the neutron flux density of the fuel sub-region is extracted by the neutronics data interface, processed, and transmitted to the heat transfer module of the COMSOL platform. The heat source distribution data of the heat transfer physics field is updated, and the operations of the COMSOL running module, the heat transfer and mechanics data transfer module, and the OpenMC running module are re-executed until convergence is achieved before proceeding to the next time step. Here, dt is the time increment from the initial time t0 to the next time step.
9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the multiphysics coupling calculation method based on the COMSOL platform as described in any one of claims 1 to 7.
10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the multiphysics coupling calculation method based on the COMSOL platform as described in any one of claims 1 to 7.