Software coupling calculation method, system and equipment for multi-scale reactor core and medium

Abstract

The invention relates to the technical field of reactor thermal hydraulic research, in particular to a software coupling calculation method, system, equipment and medium for a multi-scale reactor core, and the method comprises the following steps: dividing a pressure vessel computational domain into an active area upstream flow field, an active area and an active area downstream flow field; calculating the active area by adopting a sub-channel program to obtain inlet and outlet pressure drop of each fuel assembly, calculating the downstream flow field of the active area by adopting CFD to obtain outlet pressure of each fuel assembly, updating the inlet pressure of each fuel assembly according to the inlet and outlet pressure drop and the outlet pressure, and calculating the inlet pressure of each fuel assembly according to the updated inlet pressure. According to the updated inlet pressure, a CFD program is adopted to calculate the upstream flow field of the active area, and the new inlet flow of each fuel assembly is obtained; and iterative calculation is carried out until the new inlet flow meets the convergence condition, and full-reactor-core calculation is completed. According to the method, the advantages of a sub-channel program and a CFD program are integrated, program advantage complementation is achieved, and the major engineering problem of multi-scale reactor core full-scale accurate calculation can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reactor thermal hydraulic research, and in particular to a software coupling calculation method, system, equipment and medium for a multi-scale core. Background Art

[0002] A multi-scale core means that the reactor core is composed of relatively independent fuel assemblies; the internal flow channels of the assemblies can be decomposed into relatively independent sub-channels, and the size of the sub-channels and the core differ by 3 to 5 orders of magnitude, so it is called a multi-scale structure.

[0003] At present, for the design of the core, the sub-channel program can be used for thermal safety analysis; for closed fuel assemblies, the complex in-core structure of the upper and lower chambers of the core has a great influence on the flow distribution of each assembly, but because the sub-channel program is one-dimensional, it cannot reflect the influence of the complex flow field of the upper and lower chambers of the core on the inlet and outlet conditions of the fuel assembly. In addition, due to the radial non-uniform distribution of the core power, the internal flow state of each fuel assembly is not the same under hot conditions, and the flow redistribution leads to unequal flow of fuel assemblies, but the existing sub-channel program always assumes that the flow distribution of each fuel assembly is equal, which will bring about a large deviation. Computational fluid dynamics software (CFD) has developed rapidly and can be applied to different geometric structures, and can obtain three-dimensional local flow field and temperature field information; however, due to the local boiling in the channel inside the core active area, the CFD calculation accuracy will decrease; at the same time, the channel size is in the order of millimeters. If CFD is used to carry out full core calculations, the grid scale is too large, the calculation speed is slow, and the calculation accuracy and efficiency cannot meet the engineering requirements.

[0004] Based on this, how to achieve accurate and efficient calculation of the entire core scale is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a software coupling calculation method, system, equipment and medium for a multi-scale core. Based on the idea of ​​spatial decomposition and integrating the advantages of sub-channel programs and CFD programs, on the one hand, it can efficiently calculate and ensure the accuracy of the calculation of the internal flow and heat transfer information of the fuel assembly; on the other hand, it can accurately reflect the influence of the complex structures upstream and downstream of the active area on the flow field and boundary conditions, improve the accuracy of thermal safety design analysis, and solve the technical problem of how to achieve full-scale accurate and efficient calculation of the core.

[0006] The present invention is implemented by the following technical solution: a software coupling calculation method for a multi-scale core comprises the following steps:

[0007] The pressure vessel calculation domain is divided into an upstream flow field of the active area, an active area, and a downstream flow field of the active area, wherein the active area is a region formed by the parallel connection of the fuel assemblies in the pressure vessel;

[0008] Given initial parameters, the initial parameters include the total inlet flow rate of the core, assuming that the initial inlet flow rates of each fuel assembly are the same, using a subchannel program to perform fluid-solid coupling calculations on each fuel assembly in the active area to obtain the inlet and outlet pressure drops of each fuel assembly, and using a CFD program to calculate the fluid conditions of the flow field downstream of the active area to obtain the outlet pressure of each fuel assembly;

[0009] The inlet pressure of each fuel assembly is updated according to the inlet and outlet pressure drops and the outlet pressure, and the updated inlet pressure is returned as the boundary condition of the CFD program calculation of the flow field upstream of the active area to obtain a new inlet flow rate of each fuel assembly;

[0010] The new inlet flow rate of each fuel assembly is iteratively calculated until the new inlet flow rate meets the convergence condition, and the calculation of the entire core is completed.

[0011] According to a preferred embodiment, the expression of the initial inlet flow rate is as follows:

[0012]

[0013] In the above formula, W I represents the initial inlet flow rate of fuel assembly I, W T represents the total inlet flow rate of the core, N represents the number of fuel assemblies in the pressure vessel, Indicates the core bypass leakage flow.

[0014] According to a preferred embodiment, when the fluid condition of the flow field downstream of the active area is calculated using a CFD program, the reference pressure of the coolant outlet surface of the flow field downstream of the active area is set to zero.

[0015] According to a preferred embodiment, the expression for updating the inlet pressure is as follows:

[0016] P I,in =ΔP I +P I,out

[0017] In the above formula, P I,in represents the inlet pressure of fuel assembly I, ΔP I represents the inlet and outlet pressure drop of fuel assembly I, P I,out Indicates the outlet pressure of fuel assembly I.

[0018] According to a preferred embodiment, the convergence condition is that the maximum inlet flow fluctuation of adjacent steps is less than the flow error limit, and the expression is as follows:

[0019] max(|W I,in -W I,in,old |)≤ε W

[0020] In the above formula, W I,in represents the new inlet flow rate of fuel assembly I, W I,in,old represents the inlet flow rate of fuel assembly I in the previous iteration, ε W Indicates the flow error limit, and max() indicates the maximum value.

[0021] The present invention also provides a software coupling computing system for a multi-scale core, comprising:

[0022] A computational domain division module, used to divide the computational domain of the pressure vessel into an upstream flow field of the active region, an active region, and a downstream flow field of the active region, wherein the active region is a region formed by the parallel connection of various fuel assemblies in the pressure vessel;

[0023] The active zone calculation module is used to give initial parameters, including the total flow rate at the inlet of the core, and to perform fluid-solid coupling calculations on each fuel assembly in the active zone using a sub-channel program, assuming that the initial inlet flow rates of each fuel assembly are the same, to obtain the inlet and outlet pressure drops of each fuel assembly;

[0024] The active area downstream flow field calculation module is used to calculate the fluid conditions of the active area downstream flow field using the CFD program to obtain the outlet pressure of each fuel assembly;

[0025] An assembly inlet pressure field updating module, used to update the inlet pressure of each fuel assembly according to the inlet and outlet pressure drops and the outlet pressure;

[0026] The active zone upstream flow field calculation module is used to return the updated inlet pressure as the boundary condition for the active zone upstream flow field CFD program calculation to obtain the new inlet flow of each fuel assembly;

[0027] The convergence judgment module is used to iteratively calculate the new inlet flow rate of each fuel assembly until the new inlet flow rate meets the convergence condition, thereby completing the calculation of the entire core.

[0028] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described above when executing the computer program.

[0029] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method described above is implemented.

[0030] The technical solution of a software-coupled calculation method, system, equipment and medium for a multi-scale core provided by the present invention has at least the following advantages and beneficial effects: (1) Based on the idea of ​​spatial decomposition, the present invention divides the core into partitions and performs calculations separately, thereby reducing the scale and difficulty of core calculations; (2) Calculation programs of different scales are adopted according to the characteristics of different partitions, and the advantages of sub-channel programs and CFD programs are integrated to achieve complementary program advantages; (3) The sub-channel program is used to calculate the active zone, which can efficiently calculate and ensure the accuracy of the calculation of the internal flow and heat transfer information of the fuel assembly; the CFD is used to calculate the upstream and downstream flow fields, which can accurately reflect the influence of the complex structures upstream and downstream of the active zone on the flow field and boundary conditions, thereby improving the accuracy of thermal safety design analysis, thereby effectively solving the major engineering problem of full-scale precise calculation of multi-scale cores. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of a software coupling calculation method for a multi-scale core provided in Example 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of core partitioning provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Example 1

[0035] Figure 1 This is a flow chart of the software coupling calculation method for the multi-scale core provided by an embodiment of the present invention. Figure 1 As shown, the software coupling calculation method of the multi-scale core includes the following steps:

[0036] Step 1: See Figure 2 As shown, the calculation domain of the pressure vessel is divided into the flow field upstream of the active area, the active area, and the flow field downstream of the active area.

[0037] Among them, the flow field upstream of the active area includes the coolant inlet, the downcomer annulus and the lower chamber of the core; at the same time, it can be seen that the outlet surfaces of the flow field upstream of the active area are also the inlets of each fuel assembly. The geometric structure of the flow field upstream of the active area is complex, and the flow field and velocity field may be non-uniform, which has an important influence on the total pressure drop of the core and the flow distribution of each fuel assembly.

[0038] The active zone is the area formed by the parallel connection of various fuel assemblies in the pressure vessel, which involves single-phase or two-phase fluid-solid coupled heat transfer. At the same time, it can be seen that the outlet surface of each fuel assembly is also the inlet surface of the downstream flow field of the active zone. The geometric structures of each fuel assembly are basically the same, but the thermal parameters such as power and flow rate are different.

[0039] The flow field downstream of the active area includes the upper chamber of the core and the coolant inlet, which provides outlet back pressure for the fuel assembly.

[0040] This embodiment is based on the idea of ​​spatial decomposition, divides the core into partitions and performs calculations separately, which can effectively reduce the scale and difficulty of core calculations.

[0041] Step 2: Initialize fuel assembly flow.

[0042] Given the initial parameters, parameters such as the total flow rate at the core inlet, total power, power distribution, reference pressure and inlet temperature.

[0043] In this embodiment, it is assumed that the initial inlet flow rate of each fuel assembly is the same, and the initial inlet flow rate is given; the expression of the initial inlet flow rate is as follows:

[0044]

[0045] In the above formula, W I represents the initial inlet flow rate of fuel assembly I, W T represents the total inlet flow rate of the core, N represents the number of fuel assemblies in the pressure vessel, Indicates the core bypass leakage flow.

[0046] Step 3: Calculate the active area based on the subchannel program.

[0047] Since the inlet temperature and inlet flow rate of each fuel assembly have been given in step 2, this embodiment transfers the initial inlet flow rate and inlet temperature to the sub-channel program, uses the sub-channel program to solve the fuel assembly area, and performs fluid-solid coupling calculations on each fuel assembly in the active area, that is, solves the fluid-solid coupling heat transfer problem of the fuel assembly.

[0048] After the sub-channel program calculation is completed, the inlet and outlet pressure drops of each fuel assembly and the flow rate and temperature at the outlet of each fuel assembly can be obtained. The above parameters are also the parameters of the inlet of the flow field downstream of the active area.

[0049] It should be noted that this embodiment uses a sub-channel program to calculate the active area, which can efficiently calculate and ensure the accuracy of the calculation of the internal flow and heat transfer information of the fuel assembly.

[0050] Step 4: Calculate the flow field downstream of the active area based on CFD.

[0051] The inlet surface of the flow field downstream of the active area is the outlet surface of each fuel assembly. After calculation in step 3, the inlet flow rate of the flow field downstream of the active area is given, and the reference pressure of the outlet surface, i.e., the coolant outlet, is set to zero. For the single-phase flow problem, this embodiment uses a CFD program to calculate the fluid conditions of the flow field downstream of the active area, and the outlet pressure of each fuel assembly can be obtained.

[0052] Step 5: Update the fuel assembly inlet pressure field.

[0053] In this embodiment, the inlet pressure of each fuel assembly is updated according to the inlet and outlet pressure drops obtained in step 3 and the outlet pressure obtained in step 4; the expression for updating the inlet pressure is as follows:

[0054] P I,in =ΔP I +P I,out

[0055] In the above formula, P I,in represents the inlet pressure of fuel assembly I, ΔP I represents the inlet and outlet pressure drop of fuel assembly I, P I,out Indicates the outlet pressure of fuel assembly I.

[0056] Step 6: Calculate the flow field upstream of the active area based on CFD.

[0057] Similar to the flow field downstream of the active area, the flow field upstream of the active area is also a single-phase flow and the total inlet flow rate is given; after the calculation in step 5 is completed, the outlet pressures of the flow field upstream of the active area, that is, the inlet pressures of each fuel assembly, have been updated in step 5. Therefore, the updated inlet pressure can be used as the boundary condition for the CFD program calculation of the flow field upstream of the active area to obtain the new inlet flow rate of each fuel assembly.

[0058] It should be noted that this embodiment uses CFD to calculate the upstream and downstream flow fields, which can accurately reflect the impact of the complex structures upstream and downstream of the active area on the flow field and boundary conditions, and improve the accuracy of thermal safety design analysis.

[0059] Step 7: Calculate the three partitions in coupling mode and judge the convergence.

[0060] Iterate and calculate the new inlet flow rate of each fuel assembly until the new inlet flow rate meets the convergence condition and completes the calculation of the entire core. If the convergence condition is not met, return to step 3 and continue iterating.

[0061] In this embodiment, the convergence condition is that the maximum inlet flow fluctuation of adjacent steps is less than the flow error limit, and the expression is as follows:

[0062] max(|W I,in -W I,in,old |)≤ε W

[0063] In the above formula, W I,in represents the new inlet flow rate of fuel assembly I, W I,in,old represents the inlet flow rate of fuel assembly I in the previous iteration, ε W Indicates the flow error limit, which can be set to 0.01, and max() indicates the maximum value.

[0064] In summary, this embodiment adopts calculation programs of different scales according to the characteristics of different partitions, integrates the advantages of sub-channel programs and CFD programs, and realizes the complementary advantages of sub-channel programs and CFD programs, thereby effectively solving the major engineering problem of full-scale precise calculation of multi-scale cores.

[0065] Example 2

[0066] Based on the technical solution provided in Example 1, this embodiment provides a software coupling computing system for a multi-scale core, which includes: a computing domain division module, an active area computing module, an active area downstream flow field computing module, a component inlet pressure field updating module, an active area upstream flow field computing module, and a convergence judgment module.

[0067] Among them, the calculation domain division module is used to divide the pressure vessel calculation domain into the upstream flow field of the active area, the active area and the downstream flow field of the active area, wherein the active area is the area formed by the parallel connection of each fuel assembly in the pressure vessel; the active area calculation module is used to pass the initial inlet flow and inlet temperature to the sub-channel program to perform fluid-solid coupling calculation of each fuel assembly in the active area, and obtain the inlet and outlet pressure drops of each fuel assembly; the active area downstream flow field calculation module is used to calculate the fluid conditions of the active area downstream flow field using the CFD program, and obtain the outlet pressure of each fuel assembly; the assembly inlet pressure field update module is used to update the inlet pressure of each fuel assembly according to the inlet and outlet pressure drops and outlet pressures; the active area upstream flow field calculation module is used to return the updated inlet pressure as the boundary condition for the active area upstream flow field CFD program calculation, and obtain the new inlet flow of each fuel assembly; the convergence judgment module is used to iteratively calculate the new inlet flow of each fuel assembly until the new inlet flow meets the convergence conditions and completes the calculation of the entire core.

[0068] Example 3

[0069] Based on the technical solution provided in Example 1, this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method in Example 1 is implemented.

[0070] Example 4

[0071] Based on the technical solution provided in Example 1, this embodiment provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method in Example 1 is implemented.

[0072] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A software coupling calculation method for a multi-scale core, characterized in that: The steps include: The pressure vessel calculation domain is divided into an upstream flow field of the active area, an active area, and a downstream flow field of the active area, wherein the active area is a region formed by the parallel connection of the fuel assemblies in the pressure vessel; Given initial parameters, the initial parameters include the total inlet flow rate of the core, assuming that the initial inlet flow rates of each fuel assembly are the same, using a subchannel program to perform fluid-solid coupling calculations on each fuel assembly in the active area to obtain the inlet and outlet pressure drops of each fuel assembly, and using a CFD program to calculate the fluid conditions of the flow field downstream of the active area to obtain the outlet pressure of each fuel assembly; The inlet pressure of each fuel assembly is updated according to the inlet and outlet pressure drops and the outlet pressure, and the updated inlet pressure is returned as the boundary condition of the CFD program calculation of the flow field upstream of the active area to obtain a new inlet flow rate of each fuel assembly; The new inlet flow rate of each fuel assembly is iteratively calculated until the new inlet flow rate meets the convergence condition, and the calculation of the entire core is completed.

2. The software coupling calculation method for a multi-scale core according to claim 1, characterized in that: The expression of the initial inlet flow rate is as follows: In the above formula, W I represents the initial inlet flow rate of fuel assembly I, W T represents the total inlet flow rate of the core, N represents the number of fuel assemblies in the pressure vessel, Indicates the core bypass leakage flow.

3. The software coupling calculation method for a multi-scale core according to claim 2, characterized in that: When the CFD program is used to calculate the fluid conditions of the flow field downstream of the active area, the reference pressure of the coolant outlet surface of the flow field downstream of the active area is set to zero.

4. The software coupling calculation method for a multi-scale core according to claim 3, characterized in that: The expression for the inlet pressure update is as follows: P I，in =D P +P I,out In the above formula, P I,in represents the inlet pressure of fuel assembly I, ΔP I represents the inlet and outlet pressure drop of fuel assembly I, P I,out Indicates the outlet pressure of fuel assembly I.

5. The software coupling calculation method for a multi-scale core according to claim 4, characterized in that: The convergence condition is that the maximum inlet flow fluctuation of adjacent steps is less than the flow error limit, and the expression is as follows: max(|W I，in -W I,in,old |)≤ε W In the above formula, W I,in represents the new inlet flow rate of fuel assembly I, W I,in,old represents the inlet flow rate of fuel assembly I in the previous iteration, ε W Indicates the flow error limit, and max() indicates the maximum value.

6. A software-coupled computing system for a multi-scale core, characterized in that: include: A computational domain division module, used to divide the computational domain of the pressure vessel into an upstream flow field of the active region, an active region, and a downstream flow field of the active region, wherein the active region is a region formed by the parallel connection of various fuel assemblies in the pressure vessel; The active zone calculation module is used to give initial parameters, including the total flow rate at the inlet of the core, and to perform fluid-solid coupling calculations on each fuel assembly in the active zone using a sub-channel program, assuming that the initial inlet flow rates of each fuel assembly are the same, to obtain the inlet and outlet pressure drops of each fuel assembly; The active area downstream flow field calculation module is used to calculate the fluid conditions of the active area downstream flow field using the CFD program to obtain the outlet pressure of each fuel assembly; An assembly inlet pressure field updating module, used to update the inlet pressure of each fuel assembly according to the inlet and outlet pressure drops and the outlet pressure; The active zone upstream flow field calculation module is used to return the updated inlet pressure as the boundary condition for the active zone upstream flow field CFD program calculation to obtain the new inlet flow of each fuel assembly; The convergence judgment module is used to iteratively calculate the new inlet flow rate of each fuel assembly until the new inlet flow rate meets the convergence condition, thereby completing the calculation of the entire core.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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