Corrosion product deposition behavior numerical simulation analysis method and related device

Abstract

The invention relates to a corrosion product deposition behavior numerical simulation analysis method and a related device, which are applied to a heat exchanger of a nuclear power plant residual heat removal system, and the method comprises the following steps: S1, establishing a three-dimensional geometric model corresponding to the heat exchanger based on a CFD platform; s2, performing grid division on the three-dimensional geometric model, setting boundary conditions and initial conditions of the three-dimensional geometric model, and establishing a thermal hydraulic model corresponding to the three-dimensional geometric model according to the grid division, the boundary conditions and the initial conditions; s3, calculating the thermal hydraulic model based on a FLUENT platform to obtain a temperature calculation result of a preset position of the heat exchanger; and S4, when the temperature calculation result meets the design value requirement, a corrosion product deposition and migration coupling model corresponding to the heat exchanger is established, and a sediment distribution result corresponding to the heat exchanger is calculated through the corrosion product deposition and migration coupling model based on the thermal hydraulic model. The method can predict the influence of corrosion product migration and deposition on the thermal performance of the heat exchanger.

Description

Technical Field

[0001] This invention relates to the field of nuclear power technology, and more specifically, to a numerical simulation analysis method and related apparatus for corrosion product deposition behavior. Background Technology

[0002] Radiation dose levels are directly related to radioactive materials in the primary loop of a nuclear power plant. Accurate and reliable source term analysis can guide the control and optimization of radiation protection in in-service nuclear facilities, and also provide data support for the disposal of decommissioned nuclear facilities and the management of radioactive waste. Radioactive source terms in the primary loop of a nuclear power plant can be divided into three main categories: fission products from leaks in core assemblies, activated corrosion products deposited on the surfaces of equipment or components, and activated products generated by coolant activation. Among these, activated corrosion product source terms are particularly critical. Corrosion or abrasion products on the surface of structural materials in the coolant system are carried by the coolant to the core or neutron irradiation area, where they are activated by neutron bombardment; or materials located in the core or neutron irradiation area are first activated by neutron bombardment, and then oxidized and corroded during contact with the coolant, thus forming activated corrosion products in the circulation loop. Activated corrosion products deposited on pipe walls and in the coolant will cause an increase in radiation dose rate when circulating in the loop. Assessing the content and distribution of activated corrosion products has become an important task in the design, operation, and maintenance of pressurized water reactors. Currently, there is limited content evaluating the impact of corrosion product migration and deposition behavior on heat exchanger performance in waste heat removal systems. Domestic and international calculation models and programs use empirical models or semi-empirical and semi-mechanistic models for simulation calculations. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a numerical simulation analysis method for the deposition behavior of corrosion products, addressing some of the technical deficiencies of the prior art.

[0004] The technical solution adopted by this invention to solve its technical problem is: to construct a numerical simulation analysis method for corrosion product deposition behavior, applied to the heat exchanger of the waste heat removal system in a nuclear power plant, the analysis method comprising the following steps:

[0005] S1. Establish a three-dimensional geometric model of the heat exchanger based on the CFD platform;

[0006] S2. Mesh the three-dimensional geometric model and set the boundary conditions and initial conditions of the three-dimensional geometric model to establish a thermal-hydraulic model corresponding to the three-dimensional geometric model based on the mesh, the boundary conditions and the initial conditions;

[0007] S3. Calculate the thermal-hydraulic model based on the FLUENT platform to obtain the temperature calculation results at the preset position of the heat exchanger;

[0008] S4. When the temperature calculation result meets the design value requirements, establish a corrosion product deposition and migration coupling model corresponding to the heat exchanger, and calculate the deposition distribution result corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition and migration coupling model.

[0009] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, in step S1, generating the three-dimensional geometric model corresponding to the heat exchanger based on a CFD platform includes:

[0010] A simplified model of the heat exchanger, including the primary tube bundle region and the secondary tube shell region, is constructed based on the porous media model. In the simplified model, the water ring structure corresponding to the cooling water inlet on the right side of the secondary fluid domain of the heat exchanger is set as three rectangular inlets.

[0011] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, the primary side tube bundle region includes a lower chamber, tube sheet, straight tube region, and curved tube region; the secondary side tube shell region includes a tube bundle heating region and a descending section.

[0012] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior according to the present invention, in step S2, the meshing of the three-dimensional geometric model includes:

[0013] The three-dimensional geometric model was divided into unstructured hexagonal meshes based on the FLUENT platform.

[0014] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, step S4, establishing the corrosion product deposition and migration coupling model corresponding to the heat exchanger, includes:

[0015] Based on the precipitation process corresponding to the corrosion products and the regional mass transfer process corresponding to the corrosion products, a coupled deposition and migration model of the corrosion products corresponding to the heat exchanger is constructed.

[0016] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, the deposition process corresponding to the corrosion products includes: particulate corrosion product deposition effect, dissolution of soluble state and crystallization.

[0017] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, in step S4, the calculation of the deposition distribution results corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition-migration coupling model includes: obtaining the mass of corrosion product deposition in the heat exchanger based on the following formula.

[0018]

[0019] Where I represents the mass of corrosion products in the primary loop of the heat exchanger, and V DS V represents the dissolution rate of deposited corrosion products. PD V represents the deposition rate of particulate corrosion products. CR The crystallization rate of corrosion products occurring in the heat exchanger; and

[0020] The dissolution rate of the deposited corrosion products satisfies:

[0021]

[0022] Among them, h rl C is the dissolution and release coefficient of deposited corrosion products. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height;

[0023] The deposition rate of the particulate corrosion products satisfies:

[0024]

[0025] Among them, K PD C is the mass transfer coefficient for particulate corrosion product deposition. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height;

[0026] The crystallization rate of the corrosion products occurring in the heat exchanger satisfies:

[0027]

[0028] Among them, h CR C is the crystallinity coefficient of the dissolved corrosion products. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import and export height.

[0029] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, in step S4, the calculation of the deposition distribution results corresponding to the heat exchanger based on the thermal-hydraulic model using the corrosion product deposition-migration coupling model includes:

[0030] A time step is set, and the heat exchanger starts cyclic calculation from the initial state according to the time step, wherein the heat exchanger does not contain deposits in the initial state.

[0031] Preferably, in the numerical simulation analysis method for corrosion product deposition behavior described in this invention, the time step is 200 days.

[0032] Preferably, the electronic device of the present invention includes a memory and a processor;

[0033] The memory is used to store computer programs;

[0034] The processor is used to execute the computer program to implement the method described above.

[0035] Preferably, in a computer storage medium of the present invention, a computer program is stored thereon, which, when executed by a processor, implements the method described above.

[0036] The numerical simulation analysis method and related apparatus for corrosion product deposition behavior of the present invention have the following beneficial effects: they can predict the migration and deposition of corrosion products and thus evaluate their impact on the thermal performance of heat exchangers. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0038] Figure 1 This is a flowchart of an embodiment of a numerical simulation analysis method for corrosion product deposition behavior according to the present invention;

[0039] Figure 2 This is a schematic diagram of the axial distribution of sediment thickness in one embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the axial distribution of sediment mass according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram illustrating the change in deposition thickness at different locations of the heat transfer tube over time in one embodiment of the present invention. Detailed Implementation

[0042] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] like Figure 1 The image illustrates an embodiment of a numerical simulation analysis method for corrosion product deposition behavior according to the present invention. This method is primarily used in heat exchangers of waste heat removal systems in nuclear power plants. Figure 1An embodiment of the numerical simulation analysis method for corrosion product deposition behavior of the present invention is shown, comprising the following steps: S1, establishing a three-dimensional geometric model corresponding to the heat exchanger based on a CFD platform; S2, meshing the three-dimensional geometric model and setting the boundary conditions and initial conditions of the three-dimensional geometric model to establish a thermal-hydraulic model corresponding to the three-dimensional geometric model based on the meshing, the boundary conditions and the initial conditions; S3, calculating the temperature at a preset location of the heat exchanger based on the FLUENT platform; S4, when the temperature calculation results meet the design requirements, establishing a corrosion product deposition and migration coupling model corresponding to the heat exchanger, and calculating the deposition distribution results corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition and migration coupling model.

[0044] Based on step S1, a heat exchanger model can be established using relevant data from the waste heat removal system heat exchanger, such as design drawings. The model establishment process relies on a CFD software platform, ultimately yielding a three-dimensional geometric model of the heat exchanger. This established three-dimensional geometric model can also be understood as the computational domain for the entire calculation process.

[0045] Furthermore, in step S1, establishing a three-dimensional geometric model of the heat exchanger based on a CFD platform includes: constructing a simplified model of the heat exchanger's primary-side tube bundle region and secondary-side shell-and-tube region based on a porous media model, and setting the water ring structure corresponding to the cooling water inlet on the right side of the secondary-side fluid domain of the heat exchanger as three rectangular inlets in the simplified model. In one embodiment, the primary-side tube bundle region includes a lower chamber, tube sheet, straight tube region, and curved tube region; the secondary-side shell-and-tube region includes a tube bundle heating region and a descending section.

[0046] Specifically, due to the complex overall structure of the heat exchanger, including the shell-side feedwater ring and counter-current baffles, simplifications were implemented during modeling. While omitting external components, the cooling water inlet on the right side of the secondary fluid domain was simplified from a water ring structure to three rectangular inlets, and the influence of the internal baffles was ignored. Both the primary and secondary tube bundle regions were simplified using a porous media model. The model is divided into two parts: the primary tube bundle region and the secondary tube-shell region. The primary tube bundle region is further divided into four parts: the lower chamber, tube sheet, straight tube region, and curved tube region. The secondary side is divided into the tube bundle heating region and the descending section. Furthermore, while omitting external components, the cooling water inlet on the right side of the secondary fluid domain was simplified from a water ring structure to three equally sized rectangular inlets on the left side with an included angle of 30°, and the influence of the internal baffles on the secondary fluid was ignored.

[0047] Based on step S2, both the primary and secondary tube bundle regions are simplified using a porous medium model. While this modeling method significantly reduces computational complexity, it results in complex geometric overlap in the mesh of the U-shaped tube's curved region. The original geometric modeling process failed to fully consider the spatial topological relationships of this overlapping region, leading to interference issues between the meshes of the two computational domains in the overlapping area. This may result in decreased mesh quality, the generation of negative volume elements, reduced accuracy of heat transfer calculations between the primary and secondary sides, and difficulties in numerical solution convergence. To ensure the geometric integrity of the computational domain and the accuracy of multiphysics coupling calculations, [further steps are taken].

[0048] In one embodiment, the three-dimensional geometric model can be meshed using an unstructured hexagonal mesh based on the FLUENT platform. Specifically, after obtaining the three-dimensional geometric model, since the heat exchanger model is complex and not composed of regular geometric structures, the computational domain is meshed using FLUENT meshing software to ensure mesh quality. In the U-shaped tube bending region of the model, the mesh is prone to complex geometric overlap, leading to interference between the two computational domains and the generation of negative volume elements. To ensure the geometric integrity of the computational domain and the accuracy of the calculation, mesh replication technology is used for mesh processing, ultimately obtaining the complete mesh of the heat exchanger.

[0049] In step S2, the boundary conditions of the three-dimensional geometric model can be set based on Table 1 below. The required boundary conditions include inlet mass flow rate and temperature, and outlet boundary conditions:

[0050] Table 1 Boundary Condition Settings

[0051]

[0052] Based on step S3, after running the established porous media model of the heat exchanger on the FLUENT platform for a certain time step, the steady-state operating conditions are obtained, and the calculation results are evaluated. The secondary side cooling water has the lowest temperature at the upper inlet on the shell side. After flowing through the tube bundle area and being heated by the coolant, the temperature in the tube bundle area gradually increases, with the hot side temperature being higher than the cold side temperature, and the highest temperature occurring at the connection between the U-tube and the lower right chamber. Due to jets at the primary side coolant inlet, the lower right chamber, and the lower part of the hot side of the U-tube, and vortices at the bends, the heat transfer coefficients in these areas are relatively high. The secondary side cooling water flows in at the inlet and, under the action of strong turbulence, scours the tube bundle area, resulting in high flow velocities at the inlet and outlet. The steady-state operating conditions calculation results of the porous media model of the heat exchanger are compared with the design conditions. The calculated inlet and outlet temperatures on both sides of the heat exchanger have errors within 2% compared to the design values. Therefore, the accuracy and precision of this thermal-hydraulic model are high, and further calculations and analyses of the migration characteristics of corrosion deposit products will be conducted.

[0053] Based on step S4, after determining that the thermal-hydraulic model meets the design requirements, the deposition distribution results corresponding to the heat exchanger can be calculated based on the thermal-hydraulic model through the corrosion product deposition and migration coupling model.

[0054] In the specific calculation process, a coupled deposition and migration model of the corrosion products in the heat exchanger can be constructed based on the precipitation process corresponding to the corrosion products and the regional mass transfer process corresponding to the corrosion products. This is because particulate corrosion products in the coolant not only have an interconversion relationship with dissolved corrosion products in the coolant, but also interact with the surface of the structural material, such as deposition (PD) that occurs on the structural surface at any temperature. In the RRA system heat exchanger, because the temperature of the bulk coolant is higher than that of the coolant near the wall, the solubility of corrosion products in the bulk coolant is lower than that of corrosion products near the wall, resulting in a greater dissolution effect of the deposited layer occurring in the region.

[0055] Based on the above process, the following step S4, which calculates the deposition distribution result of the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition-migration coupling model, includes: obtaining the deposition mass of corrosion products in the heat exchanger based on the following formula.

[0056]

[0057] Where I represents the mass of corrosion products in the primary loop of the heat exchanger, and V DS V represents the dissolution rate of deposited corrosion products. PD V represents the deposition rate of particulate corrosion products. CR The crystallization rate of corrosion products occurring in the heat exchanger; and

[0058] The dissolution rate of the deposited corrosion products satisfies:

[0059]

[0060] Among them, h rl C is the dissolution and release coefficient of deposited corrosion products. W (z)―C B (z) represents the concentration of dissolved corrosion products at the mainstream and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height;

[0061] The deposition rate of the particulate corrosion products satisfies:

[0062]

[0063] Among them, K PD C is the mass transfer coefficient for particulate corrosion product deposition.W (z)―C B (z) represents the concentration of dissolved corrosion products at the mainstream and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height;

[0064] The crystallization rate of the corrosion products occurring in the heat exchanger satisfies:

[0065]

[0066] Among them, h CR C is the crystallinity coefficient of the dissolved corrosion products. W (z)―C B (z) represents the concentration of dissolved corrosion products at the mainstream and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import and export height.

[0067] In step S4, the calculation of the deposit distribution results corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition-migration coupling model includes: setting a time step, starting the calculation cyclically according to the time step from the initial state of the heat exchanger, wherein the heat exchanger does not contain deposits in the initial state. The calculation begins at t=0, within the RRA system heat exchanger without deposits. The calculation process within one time step is as follows: first, the secondary flow field of the RRA system heat exchanger is calculated, and the concentration field of impurities is also calculated; then, the thickness of the deposits is calculated using the RRA system heat exchanger impurity deposition model, combined with the flow field parameters; finally, the fouling thermal resistance is calculated based on the fouling characteristics of the deposits; this calculation is repeated until the required calculation time is reached.

[0068] The migration and deposition of corrosion products is often a slow process, typically taking days or even years. However, CFD calculations of the flow field require sufficiently small time steps to ensure accuracy. The time steps for both methods differ by orders of magnitude. Therefore, it is impossible to simulate the entire deposition cycle using the same time step as the flow field.

[0069] In one embodiment, the time step is 200 days. Specifically, to obtain deposition results over the entire cycle and ensure their reliability, it is necessary to expand the simulation time scale. However, this expansion of the time scale has limitations. Due to the slow nature of the deposition process, it can be assumed that sediment growth has no impact on the flow field within a certain time period. Therefore, the smaller the time step, the closer the simulation results are to the experimental results. Conversely, the larger the time step, the shorter the computation time. Thus, a critical time step needs to be selected that ensures both the accuracy and computational efficiency of the calculation results. Before performing the calculation, a sensitivity analysis of the critical deposition time step is required. In a specific embodiment, 200 days is used as the critical time step for the calculation.

[0070] In the flow field calculation, the finite volume method was used to discretize the differential equations, and the Coupled algorithm was used to handle the coupled equations of velocity and pressure. Fluent UDF was used to calculate the transport and deposition processes of corrosion products.

[0071] In one specific embodiment, the computational domain inlet boundary is set at the lower right chamber inlet on the primary side and three equally sized rectangular inlets above the secondary side, while the outlet boundary is set at the lower left chamber outlet on the primary side and a circular outlet below the secondary side. In early RRA heat exchangers, the equipment cooling water flow rate in the feed water ring was uniformly distributed. The equipment cooling water entered the feed water ring and was sequentially distributed to the three flow inlets before entering the secondary side cylinder. It then entered the descending section at a uniform velocity, and the flow rate was automatically distributed according to the downstream (tube bundle region) pressure. The computational domain inlet is set as a mass-flow-inlet boundary; the outlet is set as a pressure-outlet boundary.

[0072] The CFD model (3D geometric model) corresponding to the heat exchanger in the RRA system was run on the FLUENT platform for 1×10⁻⁶ seconds. 4 After a time step, a stable temperature result was obtained. This result was compared with the initial boundary design conditions, and the calculation results are shown in Table 2.

[0073] Table 2 Calculation results of heat exchanger boundary conditions in RRA system

[0074]

[0075] Ultimately, the calculated values ​​of the heat exchanger boundary temperatures in the RRA system are basically consistent with the design values, with errors all within 0.2%, thus proving the accuracy of the CFD model corresponding to the heat exchanger in the RRA system. Specifically, the high heat transfer coefficients in the primary side coolant inlet, right lower chamber, and lower part of the hot side of the U-tube, as well as the vortex at the bend, result from jets and vortices. This is because the high flow velocity leads to more heat being carried away by the cooling water per unit time, resulting in stronger heat transfer capacity. On the secondary side, the cooling water flows in at the inlet and, under the influence of strong turbulence, washes over the tube bundle area, resulting in higher flow velocities at the inlet and outlet. Therefore, the heat transfer coefficient is higher on the cold side of the tube bundle area corresponding to the secondary side inlet and outlet regions, and the corresponding secondary side temperature is the highest, based on the same principle.

[0076] Based on the above embodiments, after 400 days of deposition, the iron ion concentration at the tube inlet is 2.00 × 10⁻⁶. -4 kg / m3, chromium ion concentration is 1.86×10 -5 kg / m3, nickel ion concentration of 5.25×10 -5 kg / m3. The final sediment concentration was found to be mainly in the lower part of the bend and the upper part of the cold side. Eddies exist in the upper part of the cold side and the bend region, and the high flow velocity scouring the tube bundle significantly increases the deposition rate, especially due to inertial deposition. Furthermore, the area with the highest sediment concentration in the entire tube bundle region is the bend region, with a deposition thickness of up to 9.19 μm. This is partly due to the greater resistance in the bend region, which facilitates the deposition of corrosion activation products. On the other hand, the bend region has an angle with the vertical plane, so under the influence of gravity, corrosion activation products also tend to accumulate on its surface.

[0077] That is, the areas with higher deposition thickness are at the coolant inlet and outlet. The deposition thickness is greatest at the bottom of the coolant outlet, gradually decreasing with increasing height, and is smallest at the top. Due to the relatively high flow velocity at the inlet boundary conditions, there is jetting of coolant at both the inlet and outlet, which increases the friction velocity and deposition rate. At the same time, under the influence of gravity, corrosion products are mostly deposited at the bottom of the outlet.

[0078] Reference Figure 2 and Figure 3 The figures show the axial distribution of deposit thickness and mass on the cold and hot sides of the heat transfer tubes in the RRA system after 400 days of deposition. As can be seen from the figures, the deposit mass and thickness on the cold side of the heat transfer tubes are greater than those on the hot side. This phenomenon is mainly because the fluid velocity increases after flowing from the hot side into the bend region and experiencing eddies, resulting in a generally higher velocity on the cold side than on the hot side, thus increasing the friction velocity and consequently the deposit mass and thickness. Simultaneously, the deposition thickness on the cold side of the heat transfer tubes decreases with increasing tube bundle height, but increases significantly after reaching the bend region; the deposition thickness on the hot side increases with increasing tube bundle height, reaching its maximum value in the bend region.

[0079] Meanwhile, points were taken at both the straight and curved sections of the pipe, for reference. Figure 4 Based on the analysis of the deposition thickness at different locations of the heat transfer tube over time, it can be seen that the deposition thickness increases linearly with deposition time. The deposition thickness is larger at 1.0m on the cold side and 7.0m in the bend area, while the deposition thickness is smaller at 1.0m on the hot side.

[0080] Understandably, calculations after 400 days of deposition indicate that deposits in the heat exchanger tube bundles of the RRA system are mainly distributed in the upper part of the cold side and the lower part of the bend area. Velocity, gravity, and flow resistance significantly influence deposition formation. Flow velocity is the primary factor leading to higher deposition on the cold side of the heat exchanger; as flow velocity increases, the frictional velocity of the coolant scouring the tube bundle increases, resulting in a higher deposition rate and more deposits. Deposition in the lower part of the bend area is influenced not only by the presence of eddies leading to high-velocity scouring of the tube bundle but also by increased flow resistance, resulting in higher deposition volume. Furthermore, gravity also affects the deposition location due to the angle with the straight tubes. The final distribution prediction results are obtained.

[0081] Furthermore, an electronic device according to the present invention may further include a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to implement the above-described method. Specifically, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, when the computer program is downloaded, installed, and executed by an electronic device, it performs the functions defined in the methods of the embodiments of the present invention. The electronic device in the present invention may be a terminal such as a laptop, desktop computer, tablet computer, or smartphone, or it may be a server.

[0082] Furthermore, this invention provides a computer storage medium storing a computer program, which, when executed by a processor, implements any of the methods described above. Specifically, it should be noted that the computer-readable medium described above can be a computer-readable signal medium, a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. The transmitted data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0083] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.

[0084] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A numerical simulation analysis method for the deposition behavior of corrosion products, characterized in that, The analytical method for a heat exchanger used in a waste heat removal system of a nuclear power plant includes the following steps: S1. Establish a three-dimensional geometric model of the heat exchanger based on the CFD platform; S2. Mesh the three-dimensional geometric model and set the boundary conditions and initial conditions of the three-dimensional geometric model to establish a thermal-hydraulic model corresponding to the three-dimensional geometric model based on the mesh, the boundary conditions and the initial conditions; S3. Calculate the thermal-hydraulic model based on the FLUENT platform to obtain the temperature calculation results at the preset position of the heat exchanger; S4. When the temperature calculation result meets the design value requirements, establish a corrosion product deposition and migration coupling model corresponding to the heat exchanger, and calculate the deposition distribution result corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition and migration coupling model.

2. The numerical simulation analysis method for corrosion product deposition behavior according to claim 1, characterized in that, In step S1, establishing the three-dimensional geometric model of the heat exchanger based on the CFD platform includes: A simplified model of the heat exchanger, including the primary tube bundle region and the secondary tube shell region, is constructed based on the porous media model. In the simplified model, the water ring structure corresponding to the cooling water inlet on the right side of the secondary fluid domain of the heat exchanger is set as three rectangular inlets.

3. The numerical simulation analysis method for corrosion product deposition behavior according to claim 2, characterized in that, The primary side tube bundle region includes a lower chamber, tube sheet, straight tube region, and curved tube region; the secondary side tube shell region includes a tube bundle heating region and a descending section.

4. The numerical simulation analysis method for corrosion product deposition behavior according to claim 1, characterized in that, In step S2, meshing the three-dimensional geometric model includes: The three-dimensional geometric model was divided into unstructured hexagonal meshes based on the FLUENT platform.

5. The numerical simulation analysis method for corrosion product deposition behavior according to claim 1, characterized in that, In step S4, establishing the corrosion product deposition and migration coupling model corresponding to the heat exchanger includes: A coupled deposition and migration model of corrosion products for the heat exchanger is constructed based on the deposition process and the regional mass transfer process corresponding to the corrosion products.

6. The numerical simulation analysis method for corrosion product deposition behavior according to claim 5, characterized in that, In step S4, calculating the sediment distribution results of the heat exchanger based on the thermal-hydraulic model using the corrosion product deposition-migration coupling model includes: obtaining the mass of corrosion product deposits in the heat exchanger based on the following formula. Where I represents the mass of corrosion products in the primary loop of the heat exchanger, and V DS V represents the dissolution rate of deposited corrosion products. PD V represents the deposition rate of particulate corrosion products. CR The crystallization rate of corrosion products occurring in the heat exchanger; and The dissolution rate of the deposited corrosion products satisfies: Among them, h rl C is the dissolution and release coefficient of deposited corrosion products. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height; The deposition rate of the particulate corrosion products satisfies: Among them, K PD C is the mass transfer coefficient for particulate corrosion product deposition. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import / export height; The crystallization rate of the corrosion products occurring in the heat exchanger satisfies: Among them, h CR C is the crystallinity coefficient of the dissolved corrosion products. W (z)―C B (Z) represents the concentration of dissolved corrosion products at the main flow and wall surfaces of the coolant, P w For wetted perimeter, H in H out For import and export height.

7. The numerical simulation analysis method for corrosion product deposition behavior according to claim 1, characterized in that, In step S4, the calculation of the sediment distribution results corresponding to the heat exchanger based on the thermal-hydraulic model and the corrosion product deposition-migration coupling model includes: A time step is set, and the heat exchanger starts cyclic calculation from the initial state according to the time step, wherein the heat exchanger does not contain deposits in the initial state.

8. The numerical simulation analysis method for corrosion product deposition behavior according to claim 7, characterized in that, The time step is 200 days.

9. An electronic device, characterized in that, Including memory and processor; The memory is used to store computer programs; The processor is used to execute the computer program to implement the method as described in any one of claims 1 to 8.

10. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 8.

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