Full-core CFD (Computational Fluid Dynamics) program calculation method and system and electronic equipment

Abstract

The invention relates to the technical field of reactor thermal hydraulic research, in particular to a full-reactor-core CFD (computational fluid dynamics) program calculation method and system and electronic equipment.The method comprises the following steps: dividing a pressure vessel computational domain into an active area, an upstream flow field of the active area and a downstream flow field of the active area, and respectively carrying out calculation by using a CFD program; carrying out fluid-solid coupling iterative calculation on the fuel assemblies one by one in the active area to obtain the pressure drop and the average pressure drop of the fuel assemblies and determine the pressure drop deviation; performing iterative calculation on the upstream flow field of the active area and calculating a downstream flow field of the active area to obtain inlet and outlet pressures of each fuel assembly; updating the pressure drop deviation of each fuel assembly according to the inlet and outlet pressure; and iterative calculation is carried out until the new voltage drop deviation meets the first convergence condition, and calculation of the whole reactor core is completed. According to the invention, three-dimensional two-phase CFD simulation of a multi-scale reactor core can be realized, and the calculation problems of a large number of fuel assemblies, a large number of flow channels in the assemblies, fluid-solid coupling and local two phases are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reactor thermal hydraulic research, and in particular to a full core CFD program calculation method, system and electronic equipment. 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] 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. For the design of the core, CFD can be used for analysis, but the current application of CFD in the field of nuclear reactors is still limited to the analysis of local phenomena or simplified system analysis. The main difficulties are: (1) The core structure is complex and is a typical multi-scale structure. Due to the large number of water gaps inside the special fuel assembly, the number of parallel flow channels in the core is as high as several thousand. The grid scale and the total core scale differ by 4 to 5 orders of magnitude, resulting in a large grid scale and a large amount of calculation; (2) The core flow channel structure is complex, and there are various complex shapes of internal components in the upper and lower cavities, which have a direct impact on the flow field; (3) In order to improve the heat transfer efficiency, although the outlet of the pressurized water reactor is supercooled, the core power distribution is uneven, and there are hot components and hot channels. The hot channel is the key to determining the safety of core heat transfer, but supercooled boiling is common in the hot channel, and a two-phase flow model must be used for calculation, which further affects the calculation speed.

[0004] Based on this, how to achieve accurate and efficient CFD calculation of the core at all scales 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 full-core CFD program calculation method, system and electronic equipment. Based on the idea of ​​spatial decomposition, the core is divided into partitions and calculations are carried out separately, which reduces the scale and difficulty of core calculations and can realize three-dimensional two-phase CFD simulation of multi-scale cores to solve the technical problem of how to achieve accurate and efficient full-scale CFD calculations of the core.

[0006] The present invention is implemented by the following technical solution: A full core CFD program calculation method 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 flow rate at the inlet of the core, assuming that the initial inlet flow rates of each fuel assembly are the same and the initial pressure drop deviation is 0, using a CFD program to perform fluid-solid coupling iterative calculations on each fuel assembly one by one, obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and determine the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop;

[0009] The CFD program is used to iteratively calculate the flow field upstream of the active area to obtain the inlet pressure of each fuel assembly, and the CFD program is used to calculate the flow field downstream of the active area to obtain the outlet pressure of each fuel assembly;

[0010] The pressure drop deviation of each fuel assembly is updated according to the inlet pressure and the outlet pressure to obtain a new pressure drop deviation;

[0011] The new pressure drop deviation of each fuel assembly is iteratively calculated until the new pressure drop deviation meets the first convergence condition, thereby completing the calculation of the entire core.

[0012] According to a preferred embodiment, the iterative calculation of fluid-solid coupling is performed on each fuel assembly one by one using a CFD program, specifically including:

[0013] Step 1.1, given the initial inlet flow rate of each fuel assembly, perform fluid-solid coupling calculation on each fuel assembly one by one to obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies;

[0014] Step 1.2, determining the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop;

[0015] Step 1.3: Determine whether the pressure drop deviation satisfies the active region inlet and outlet pressure boundary constraint. If not, update the inlet flow rate of each fuel assembly, obtain a new inlet flow rate and return to step 1.1, where the expression of the active region inlet and outlet pressure boundary constraint is |ΔP I -ΔP AVE |≤ε P +P I,R , ΔP I represents the pressure drop of fuel assembly I, ΔP AVE represents the average pressure drop of all fuel assemblies, ε P Indicates the voltage drop deviation limit, P I,R represents the pressure drop deviation of fuel assembly I;

[0016] If yes, the iterative calculation is completed.

[0017] According to a preferred embodiment, the initial inlet flow rate of each fuel assembly is expressed as follows:

[0018]

[0019] 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, Indicates the core bypass leakage flow.

[0020] According to a preferred embodiment, the method further comprises:

[0021] Fuel assemblies are classified according to their geometric shape characteristics, and mesh division and sensitivity analysis are performed on each type of fuel assembly to obtain the optimal mesh solution for each type of fuel assembly;

[0022] The corresponding grid scheme is called to carry out fluid-solid coupling calculations for each fuel assembly.

[0023] According to a preferred embodiment, the order of performing fluid-solid coupling calculations on the fuel assemblies is from outside to inside, wherein the calculation results of the outer fuel assembly are used as the initial values ​​of the adjacent inner fuel assembly.

[0024] According to a preferred embodiment, the iterative calculation of the flow field upstream of the active area using a CFD program specifically includes:

[0025] Assuming that the initial pressures of the outlets of the flow field upstream of the active area are the same, the flow field upstream of the active area is calculated using a CFD program to obtain the flow rate of each outlet;

[0026] Compare the flow rate at each outlet with the new inlet flow rate of the fuel assembly returned in step 1.3 to determine the flow deviation;

[0027] The pressure of each outlet of the flow field upstream of the active area is updated according to the flow deviation to determine a new outlet flow of the flow field upstream of the active area;

[0028] Iteratively calculate the new outlet flow rate of the upstream flow field of the active zone until the new outlet flow rate meets the second convergence condition |W I,UP -W I |≤ε W , W I,UP represents the new outlet flow rate of the upstream flow field of the active area corresponding to the fuel assembly I, W I represents the new inlet flow rate of fuel assembly I, ε W Indicates the flow error limit.

[0029] According to a preferred embodiment, the expression for updating the voltage drop deviation is as follows:

[0030] ΔP I,R =P in -P out -ΔP AVE

[0031] In the above formula, ΔP I,R represents the new pressure drop deviation of fuel assembly I, P in Indicates the inlet pressure of the fuel assembly, P out Indicates the outlet pressure of the fuel assembly.

[0032] According to a preferred embodiment, the first convergence condition is that the fluctuation of the pressure drop deviation between adjacent steps is less than the pressure drop error limit, and the expression is as follows:

[0033]

[0034] In the above formula, represents the new pressure drop deviation of fuel assembly I after iteration n+1 times, represents the new pressure drop deviation of fuel assembly I after n iterations, ε ΔP Indicates the voltage drop error limit, and max() indicates the maximum value.

[0035] The present invention also provides a full core CFD program calculation system, comprising:

[0036] 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;

[0037] Active area calculation module, given initial parameters, the initial parameters include the total inlet flow of the core, assuming that the initial inlet flow of each fuel assembly is the same, using CFD program to perform fluid-solid coupling iterative calculation on all fuel assemblies in the active area one by one, obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and determine the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop;

[0038] The active area upstream flow field calculation module is used to iteratively calculate the active area upstream flow field using a CFD program to obtain the inlet pressure of each fuel assembly;

[0039] The active area downstream calculation module is used to calculate the flow field downstream of the active area using the CFD program to obtain the outlet pressure of each fuel assembly;

[0040] An updating module, used for updating the pressure drop deviation of each fuel assembly according to the inlet pressure and the outlet pressure to obtain a new pressure drop deviation;

[0041] The convergence judgment module is used to iteratively calculate the new pressure drop deviation of each fuel assembly until the new pressure drop deviation meets the convergence condition, thereby completing the calculation of the entire core.

[0042] 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.

[0043] The technical solutions of the full-core CFD program calculation method, system and electronic equipment provided by the present invention have at least the following advantages and beneficial effects: (1) Based on the idea of ​​spatial decomposition, the core is divided into partitions and calculations are carried out separately, which reduces the scale and difficulty of core calculations and can realize three-dimensional two-phase CFD simulation of multi-scale cores; (2) Through the iterative calculation method of operating each fuel assembly one by one, it can effectively deal with the calculation problems of a large number of fuel assemblies, a large number of flow channels inside the assemblies, and the existence of fluid-solid coupling and local two-phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic flow chart of a full core CFD program calculation method provided in Example 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of core partitioning provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] 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.

[0047] Example 1

[0048] Figure 1 A schematic diagram of a flow chart of a full core CFD program calculation method provided by an embodiment of the present invention. Figure 1 As shown, the calculation method of the full core CFD program includes the following steps:

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] This embodiment is based on the idea of ​​spatial decomposition, divides the core into partitions and carries out calculations separately, which can effectively reduce the scale and difficulty of core calculations, and transform the difficult-to-achieve refined computational engineering problem of large-scale two-phase complex flow heat transfer into a problem that can be achieved on a moderate scale, thereby realizing three-dimensional two-phase CFD simulation of multi-scale cores.

[0054] Step 2: Initialization calculation of the active area.

[0055] The initial parameters of the given core include total inlet flow, total power, power distribution, reference pressure and inlet temperature.

[0056] In this embodiment, it is assumed that the initial inlet flow rate of each fuel assembly is the same and the initial pressure drop deviation is 0; the initial inlet flow rate of each fuel assembly is expressed as follows:

[0057]

[0058] 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, Indicates the core bypass leakage flow.

[0059] Step 3: Use CFD program to perform iterative calculation of the active area.

[0060] The CFD program is used to perform iterative calculations of fluid-solid coupling on each fuel assembly one by one to obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and the pressure drop deviation of each fuel assembly is determined based on the pressure drop and the average pressure drop.

[0061] In this embodiment, it specifically includes:

[0062] Step 1.1, given the initial inlet flow rate of each fuel assembly, perform fluid-solid coupling calculation on each fuel assembly one by one to obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies;

[0063] Step 1.2, determining the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop;

[0064] Step 1.3: Determine whether the pressure drop deviation satisfies the active region inlet and outlet pressure boundary constraint. If not, update the inlet flow rate of each fuel assembly, obtain a new inlet flow rate and return to step 1.1, where the expression of the active region inlet and outlet pressure boundary constraint is |ΔP I -ΔP AVE |≤ε P +P I,R , ΔP I represents the pressure drop of fuel assembly I, ΔP AVE represents the average pressure drop of all fuel assemblies, ε P Indicates the voltage drop deviation limit, P I,R represents the pressure drop deviation of fuel assembly I;

[0065] If yes, the iterative calculation is completed.

[0066] To further speed up the calculation, the present embodiment also includes: classifying the fuel assemblies according to their geometric shape characteristics, performing grid division and sensitivity analysis on each type of fuel assembly, and obtaining the optimal grid scheme for each type of fuel assembly; calling the corresponding grid scheme to perform fluid-solid coupling calculations on each fuel assembly.

[0067] In addition, the order of fluid-solid coupling calculation for each fuel assembly is from outside to inside, where the calculation results of the outer fuel assembly are used as the initial values ​​of the adjacent inner fuel assembly.

[0068] Through the above pre-calculation steps, the correlation between the fuel assembly and the inlet flow rate can be understood, thereby saving iteration time.

[0069] It should be noted that the iterative calculation method of operating each fuel assembly one by one can effectively deal with the calculation difficulties caused by the large number of fuel assemblies, the large number of flow channels inside the assemblies, the presence of fluid-solid coupling and local two-phase.

[0070] Step 4: Use CFD program to calculate the flow field upstream of the active area.

[0071] In this embodiment, considering that the CFD program cannot handle the problem of inflow and outflow superposition, the CFD program is used to iteratively calculate the flow field upstream of the active area to obtain the inlet pressure of each fuel assembly.

[0072] In this embodiment, it specifically includes:

[0073] The total inlet flow rate is given. It is assumed that the initial pressures of the outlets of the upstream flow field of the active area are the same as the initial value of the calculation.

[0074] In this way, the flow field upstream of the active area is a basic inflow condition and outlet reference pressure flow problem. The flow field upstream of the active area is calculated using the CFD program to obtain the flow rate of each outlet.

[0075] Furthermore, the flow rate at each outlet is compared with the new inlet flow rate of the fuel assembly returned in step 1.3 to determine the flow deviation; the pressure at each outlet of the flow field upstream of the active area is updated according to the flow deviation to determine the new outlet flow rate of the flow field upstream of the active area.

[0076] Iteratively calculate the new outlet flow rate of the upstream flow field of the active zone until the new outlet flow rate meets the second convergence condition |W I,UP -W I |≤ε W , W I,UP represents the new outlet flow rate of the upstream flow field of the active area corresponding to the fuel assembly I, W I represents the new inlet flow rate of fuel assembly I, ε w Indicates the flow error limit.

[0077] Step 5: Use CFD program to calculate the flow field downstream of the active area.

[0078] The flow field downstream of the active area is a single-phase flow problem with inlet and outlet reference pressures, and no iteration is required. This embodiment uses a CFD program to calculate the flow field downstream of the active area, and the outlet pressure of each fuel assembly can be obtained.

[0079] Step 6: Update the pressure boundary of the active area.

[0080] Through steps 4 and 5, this embodiment obtains the inlet and outlet pressure distribution of each fuel assembly. This distribution reflects the influence of the upper and lower cavities of the core on the flow distribution. Therefore, the deviation of the pressure drop of each fuel assembly from the average pressure drop can be updated.

[0081] In this embodiment, it specifically includes:

[0082] The pressure drop deviation of each fuel assembly is updated according to the inlet pressure and the outlet pressure to obtain a new pressure drop deviation. The expression for updating the pressure drop deviation is as follows:

[0083] ΔP I,R =P in -P out -ΔP AVE

[0084] In the above formula, ΔP I,R represents the new pressure drop deviation of fuel assembly I, P in Indicates the inlet pressure of the fuel assembly, P out Indicates the outlet pressure of the fuel assembly.

[0085] Step 7: Perform iterative calculation on the entire core and determine the convergence.

[0086] In this embodiment, the new pressure drop deviation of each fuel assembly is iteratively calculated until the new pressure drop deviation meets the first convergence condition, thereby completing the calculation of the entire core.

[0087] The first convergence condition is that the fluctuation of the pressure drop deviation between adjacent steps is less than the pressure drop error limit, and the expression is as follows:

[0088]

[0089] In the above formula, represents the new pressure drop deviation of fuel assembly I after iteration n+1 times, represents the new pressure drop deviation of fuel assembly I after n iterations, ε ΔP Indicates the voltage drop error limit, and max() indicates the maximum value.

[0090] Example 2

[0091] Based on the technical solution provided in Example 1, this embodiment provides a full-core CFD program calculation system, including: a calculation domain division module, an active area calculation module, an active area upstream flow field calculation module, an active area downstream calculation module, an update module and a convergence judgment module.

[0092] 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 give initial parameters, and the initial parameters include the total inlet flow rate of the core. Assuming that the initial inlet flow rate of each fuel assembly is the same, the CFD program is used to perform fluid-solid coupling iterative calculation on all fuel assemblies in the active area one by one to obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and the pressure drop deviation of each fuel assembly is determined based on the pressure drop and the average pressure drop; the active area upstream flow field calculation module is used to use the CFD program to iteratively calculate the active area upstream flow field to obtain the inlet pressure of each fuel assembly; the active area downstream calculation module is used to use the CFD program to calculate the active area downstream flow field to obtain the outlet pressure of each fuel assembly; the update module is used to update the pressure drop deviation of each fuel assembly according to the inlet pressure and outlet pressure to obtain a new pressure drop deviation; the convergence judgment module is used to iteratively calculate the new pressure drop deviation of each fuel assembly until the new pressure drop deviation meets the convergence condition and the calculation of the entire core is completed.

[0093] Example 3

[0094] 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, wherein the processor implements the method described in Example 1 when executing the computer program.

[0095] 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 full core CFD program calculation method, 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 flow rate at the inlet of the core, assuming that the initial inlet flow rates of each fuel assembly are the same and the initial pressure drop deviation is 0, using a CFD program to perform fluid-solid coupling iterative calculations on each fuel assembly one by one, obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and determine the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop; The CFD program is used to iteratively calculate the flow field upstream of the active area to obtain the inlet pressure of each fuel assembly, and the CFD program is used to calculate the flow field downstream of the active area to obtain the outlet pressure of each fuel assembly; The pressure drop deviation of each fuel assembly is updated according to the inlet pressure and the outlet pressure to obtain a new pressure drop deviation; The new pressure drop deviation of each fuel assembly is iteratively calculated until the new pressure drop deviation meets the first convergence condition, thereby completing the calculation of the entire core.

2. The full core CFD program calculation method according to claim 1, characterized in that: The CFD program is used to perform iterative calculations of fluid-solid coupling on each fuel assembly one by one, specifically including: Step 1.1, given the initial inlet flow rate of each fuel assembly, perform fluid-solid coupling calculation on each fuel assembly one by one to obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies; Step 1.2, determining the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop; Step 1.3: Determine whether the pressure drop deviation satisfies the active region inlet and outlet pressure boundary constraint. If not, update the inlet flow rate of each fuel assembly, obtain a new inlet flow rate and return to step 1.1, where the expression of the active region inlet and outlet pressure boundary constraint is |ΔP I -ΔP AVE |≤ε P +P I,R , ΔP I represents the pressure drop of fuel assembly I, ΔP AVE represents the average pressure drop of all fuel assemblies, ε P Indicates the voltage drop deviation limit, P I,R represents the pressure drop deviation of fuel assembly I; If yes, the iterative calculation is completed.

3. The full core CFD program calculation method according to claim 2, characterized in that: The initial inlet flow rate of each fuel assembly is expressed 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, Indicates the core bypass leakage flow.

4. The full core CFD program calculation method according to claim 2, characterized in that: The method also includes: Fuel assemblies are classified according to their geometric shape characteristics, and mesh division and sensitivity analysis are performed on each type of fuel assembly to obtain the optimal mesh solution for each type of fuel assembly; The corresponding grid scheme is called to carry out fluid-solid coupling calculations for each fuel assembly.

5. The full core CFD program calculation method according to claim 2, characterized in that: The order of fluid-solid coupling calculation for each fuel assembly is from outside to inside, where the calculation results of the outer fuel assembly are used as the initial values ​​of the adjacent inner fuel assembly.

6. The full core CFD program calculation method according to any one of claims 2 to 5, characterized in that: The iterative calculation of the flow field upstream of the active area using the CFD program specifically includes: Assuming that the initial pressures of the outlets of the flow field upstream of the active area are the same, the flow field upstream of the active area is calculated using a CFD program to obtain the flow rate of each outlet; Compare the flow rate at each outlet with the new inlet flow rate of the fuel assembly returned in step 1.3 to determine the flow deviation; The pressure of each outlet of the flow field upstream of the active area is updated according to the flow deviation to determine a new outlet flow of the flow field upstream of the active area; Iteratively calculate the new outlet flow rate of the upstream flow field of the active zone until the new outlet flow rate satisfies the second convergence condition |W U,UP -W I |≤ε W , W I,UP represents the new outlet flow rate of the fuel assembly I corresponding to the upstream flow field of the active area, W I represents the new inlet flow rate of fuel assembly I, ε W Indicates the flow error limit.

7. The full core CFD program calculation method according to claim 6, characterized in that: The expression for updating the voltage drop deviation is as follows: ΔP I,R =P in -P out -ΔP AVE In the above formula, ΔP I,R represents the new pressure drop deviation of fuel assembly I, P in Indicates the inlet pressure of the fuel assembly, P out Indicates the outlet pressure of the fuel assembly.

8. The full core CFD program calculation method according to claim 7, characterized in that: The first convergence condition is that the fluctuation of the pressure drop deviation between adjacent steps is less than the pressure drop error limit, and the expression is as follows: In the above formula, represents the new pressure drop deviation of fuel assembly I after iteration n+1 times, represents the new pressure drop deviation of fuel assembly I after n iterations, ε ΔP Indicates the voltage drop error limit, and max() indicates the maximum value. 9.Full core CFD program calculation system, characterized by: 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; Active area calculation module, given initial parameters, the initial parameters include the total flow rate at the inlet of the core, assuming that the initial inlet flow rate of each fuel assembly is the same, using CFD program to perform fluid-solid coupling iterative calculation on all fuel assemblies in the active area one by one, obtain the pressure drop of each fuel assembly and the average pressure drop of all fuel assemblies, and determine the pressure drop deviation of each fuel assembly based on the pressure drop and the average pressure drop; The active area upstream flow field calculation module is used to iteratively calculate the active area upstream flow field using a CFD program to obtain the inlet pressure of each fuel assembly; The active area downstream calculation module is used to calculate the flow field downstream of the active area using the CFD program to obtain the outlet pressure of each fuel assembly; An updating module, used for updating the pressure drop deviation of each fuel assembly according to the inlet pressure and the outlet pressure to obtain a new pressure drop deviation; The convergence judgment module is used to iteratively calculate the new pressure drop deviation of each fuel assembly until the new pressure drop deviation meets the convergence condition, thereby completing the calculation of the entire core.

10. 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 8 is implemented.

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