A multi-channel supercritical water reactor thermal analysis method based on positioning grid correction

Abstract

The present application relates to the field of supercritical water reactor thermal analysis, in particular to a multi-channel supercritical water reactor thermal analysis method based on positioning grid correction, which comprises the following steps: obtaining real-time nuclear reactor operating condition data under target supercritical conditions; inputting the nuclear reactor operating condition data into a multi-channel supercritical water reactor thermal model to obtain global calculation results, wherein the multi-channel supercritical water reactor thermal model is a multi-channel model established based on the influence of positioning grids; and analyzing the global calculation results to obtain evaluation results of the influence of positioning grids on the performance of the reactor core under supercritical conditions. The present application does not require local positioning grid simulation, reduces the geometric dependence and the complexity of the early processing, and improves the efficiency of analyzing the thermal performance of supercritical water reactors affected by positioning grids.

Description

Technical Field

[0001] This invention relates to the field of thermal analysis of supercritical water reactors, and more specifically, to a multi-channel thermal analysis method for supercritical water reactors based on positioning grid correction. Background Technology

[0002] Supercritical water-cooled reactors (SCWRs), as a type of advanced nuclear reactor, have become an important development direction for next-generation nuclear energy technology due to their high thermal efficiency and high thermoelectric conversion efficiency. In a supercritical water reactor, the coolant (water) operates under supercritical pressure and has high specific heat capacity and thermal conductivity, enabling the reactor to operate at higher temperatures, thereby improving thermal efficiency.

[0003] For supercritical water reactors (SCWRs), the primary objective of thermal calculations is to ensure the safety and stability of the reactor under various operating conditions, particularly ensuring effective fuel rod cooling and preventing overheating and heat transfer degradation. Compared to conventional water reactors, SCWR thermal analysis presents a series of challenges, including drastic changes in physical properties, deterioration in heat transfer, and the inapplicability of turbulence models. Especially near the localized grid region, the complex geometry significantly impacts flow and heat transfer, further increasing the analytical difficulty due to the interaction between turbulence and localized heat transfer enhancement and deterioration. Currently, simulations of localized grids involve establishing a geometric model of the localized grid, calculating correction factors, and then embedding this model into a porous media model. Due to the high computational complexity and verification difficulties of supercritical water reactors, empirical formulas and simplified models are commonly used in engineering practice to approximate the effects of the localized grid. While this method is computationally efficient, its accuracy is too low, and it lacks good interpretability, thus having limited research value in the scientific research field. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-channel supercritical water reactor thermal analysis method based on positioning grid correction, so as to solve the problem that the thermal performance of supercritical water reactors affected by positioning grid cannot be conveniently and efficiently analyzed.

[0005] This invention provides a method for thermal analysis of a multi-channel supercritical water reactor based on a positioning grid correction. The method includes the following steps: acquiring real-time nuclear reactor operating condition data under target supercritical conditions, wherein the real-time nuclear reactor operating condition data includes channel geometric parameters and coolant physical property parameters of the supercritical water reactor; inputting the nuclear reactor operating condition data into a multi-channel supercritical water reactor thermal model to obtain global calculation results, wherein the multi-channel supercritical water reactor thermal model is a multi-channel model established based on the influence of the positioning grid; and analyzing the global calculation results to obtain an evaluation result of the influence of the positioning grid on the core performance under the target supercritical conditions.

[0006] Optionally, the method further includes: obtaining local calculation results based on the three-dimensional geometric model of the positioning grid and computational fluid dynamics, wherein the three-dimensional geometric model of the positioning grid includes the positioning grid structure in each channel of the supercritical water reactor and the structure of the local coolant flow region near the positioning grid; obtaining a flow resistance correction factor and a heat transfer enhancement correction factor based on the local calculation results; correcting the momentum conservation equation and energy conservation equation of the multi-channel model based on the flow resistance correction factor and the heat transfer enhancement correction factor to obtain a corrected multi-channel model, wherein the position information of the momentum conservation equation and the energy conservation equation corresponds to the position information of the flow resistance correction factor and the heat transfer enhancement correction factor; and obtaining a multi-channel supercritical water reactor thermal model based on the corrected multi-channel model and the local calculation results.

[0007] Optionally, the step of correcting the momentum conservation equation and energy conservation equation of the multi-channel model according to the flow resistance correction factor and the heat transfer enhancement correction factor to obtain the corrected multi-channel model includes: establishing momentum correction terms and energy correction terms respectively according to the flow resistance correction factor and the heat transfer enhancement correction factor; embedding the momentum correction terms and the energy correction terms into the momentum conservation equation and energy conservation equation of the multi-channel model respectively; and establishing the corrected multi-channel model according to the corrected momentum conservation equation and the energy conservation equation.

[0008] Optionally, the momentum correction term is -K spacer ·v, where K spacer is the flow resistance correction factor, and v is the fluid velocity.

[0009] Optionally, the energy correction term is Among them, Nu base Based on the Nusel number, C spacer is the heat transfer enhancement correction factor, where L is the channel length and D is the hydraulic diameter.

[0010] Optionally, obtaining local calculation results based on the three-dimensional geometric model of the positioning grid and computational fluid dynamics includes: numerically solving the three-dimensional geometric model of the positioning grid using computational fluid dynamics software to obtain the flow velocity field, pressure field, and temperature field of the coolant in the positioning grid region; obtaining flow parameters and heat transfer parameters based on the flow velocity field, the pressure field, and the temperature field; wherein the flow parameters include total pressure drop, friction coefficient, fluid density, and fluid velocity, and the heat transfer parameters include the locally corrected Nusselt number, the locally corrected Nusselt number characterizing the heat transfer efficiency enhancement effect under the influence of the positioning grid.

[0011] Optionally, obtaining the flow resistance correction factor and the heat transfer enhancement correction factor based on the local calculation results includes: calculating the flow resistance correction factor based on the flow parameters, the channel geometry parameters of the supercritical water reactor, and the flow resistance correction factor calculation formula; and calculating the heat transfer enhancement correction factor based on the heat transfer parameters, the channel geometry parameters of the supercritical water reactor, and the heat transfer enhancement correction factor calculation formula; wherein the channel geometry parameters of the supercritical water reactor include the channel length and the hydraulic diameter.

[0012] Optionally, the formula for calculating the flow resistance correction factor is as follows:

[0013]

[0014] Where, ΔP total The total pressure drop is given by f, the friction coefficient is given by L, the channel length is given by D, and the hydraulic diameter is given by K. spacer ρ is the flow resistance correction factor, ρ is the fluid density, and v is the fluid velocity.

[0015] The formula for calculating the heat transfer enhancement correction factor is as follows:

[0016]

[0017] Among them, Nu corrected Nu is the locally corrected Nusselt number. base Based on the Nusel number, C spacer Where L is the heat transfer enhancement correction factor, L is the channel length, and D is the hydraulic diameter.

[0018] Optionally, obtaining the multi-channel supercritical water reactor thermal model based on the modified multi-channel model and the local calculation results includes: acquiring the calculation results of the modified multi-channel model, wherein the position information of the calculation results of the modified multi-channel model corresponds to the position information of the local calculation results; calculating the absolute value of the difference between the local calculation results and the calculation results of the modified multi-channel model; and obtaining the multi-channel supercritical water reactor thermal model by iterating repeatedly until the absolute value is less than a preset threshold.

[0019] Optionally, the method further includes: obtaining the number of channels and channel geometric parameters based on the supercritical water reactor geometry and coolant flow path; establishing the multi-channel model based on the number of channels and the channel geometric parameters, and initializing the multi-channel model; wherein the initialization is to set the temperature, pressure, and flow velocity distribution in each channel of the multi-channel model.

[0020] Compared with existing technologies, the beneficial effects of the multi-channel supercritical water reactor thermal analysis method based on positioning grid correction provided by this invention are as follows:

[0021] This invention provides a multi-channel supercritical water reactor thermal analysis method based on a positioning grid correction. It acquires real-time nuclear reactor operating data under target supercritical conditions, including channel geometric parameters and coolant properties. This data is then input into a multi-channel supercritical water reactor thermal model to obtain global calculation results. This model is based on the influence of the positioning grid. Analysis of the global calculation results yields an evaluation of the impact of the positioning grid on core performance under supercritical conditions. This invention eliminates the need for local positioning grid simulation, i.e., the construction of a three-dimensional geometric model, reducing geometric dependence and preprocessing complexity. Only real-time nuclear reactor operating data is required to analyze the thermal performance of the supercritical water reactor, improving the efficiency of analyzing the thermal performance of supercritical water reactors affected by the positioning grid. Furthermore, the multi-channel model, compared to a porous media model, exhibits non-uniformity, enabling accurate simulation of the impact of the positioning grid on the thermal performance of the supercritical water reactor. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 A schematic flowchart illustrating a multi-channel supercritical water reactor thermal analysis method based on positioning grid correction provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic flowchart illustrating a specific method for thermal analysis of a multi-channel supercritical water reactor based on local positioning grid correction in an embodiment of the present invention.

[0025] Figure 3 This is a schematic flowchart of the correction factor extraction method in an embodiment of the present invention;

[0026] Figure 4 This is a schematic flowchart of the modified factor embedding method in an embodiment of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] This invention provides a multi-channel supercritical water reactor thermal analysis method based on a positioning grid correction. Figure 1 The diagram shows a schematic flowchart of a multi-channel supercritical water reactor thermal analysis method based on a positioning grid correction. The method includes the following steps:

[0029] S110 acquires real-time nuclear reactor operating data under target supercritical conditions.

[0030] Among them, the aforementioned real-time nuclear reactor operating data includes the channel geometry parameters and coolant physical property parameters of the supercritical water reactor;

[0031] S120, input the above nuclear reactor operating condition data into the multi-channel supercritical water reactor thermal model to obtain the global calculation results. The above multi-channel supercritical water reactor thermal model is a multi-channel model established based on the influence of the positioning grid.

[0032] S130, based on the above global calculation results, the evaluation results of the impact of the positioning grid on the core performance under the above target supercritical conditions are obtained.

[0033] Optionally, the above global calculation results can be compared and analyzed with the calculation results of the multi-channel model without the influence of the positioning grid to obtain the evaluation results of the influence of the positioning grid on the core performance under the above target supercritical conditions.

[0034] Optionally, the above method further includes: obtaining local calculation results based on the three-dimensional geometric model of the positioning grid and computational fluid dynamics (CFD), wherein the three-dimensional geometric model of the positioning grid includes the positioning grid structure in each channel of the supercritical water reactor and the structure of the local coolant flow region near the positioning grid; obtaining a flow resistance correction factor and a heat transfer enhancement correction factor based on the local calculation results; correcting the momentum conservation equation and energy conservation equation of the multi-channel model based on the flow resistance correction factor and the heat transfer enhancement correction factor to obtain a corrected multi-channel model, wherein the position information of the momentum conservation equation and the energy conservation equation corresponds to the position information of the flow resistance correction factor and the heat transfer enhancement correction factor; and obtaining a multi-channel supercritical water reactor thermal model based on the corrected multi-channel model and the local calculation results.

[0035] It should be noted that the three-dimensional geometric model of the positioning grid can accurately represent the local phenomena of flow and heat transfer in and around the positioning grid structure.

[0036] Optionally, the steps for obtaining local calculation results based on the three-dimensional geometric model of the positioning grid and computational fluid dynamics include: numerically solving the three-dimensional geometric model of the positioning grid using computational fluid dynamics software to obtain the flow velocity field, pressure field, and temperature field of the coolant in the positioning grid region; obtaining flow parameters and heat transfer parameters based on the flow velocity field, pressure field, and temperature field; wherein the flow parameters include total pressure drop, friction coefficient, fluid density, and fluid velocity, and the heat transfer parameters include the locally corrected Nusselt number, which characterizes the heat transfer efficiency enhancement effect under the influence of the positioning grid.

[0037] Optionally, the steps of obtaining the flow resistance correction factor and the heat transfer enhancement correction factor based on the above local calculation results include: calculating the flow resistance correction factor based on the above flow parameters, the channel geometry parameters of the above supercritical water reactor, and the calculation formula for the flow resistance correction factor; and calculating the heat transfer enhancement correction factor based on the above heat transfer parameters, the channel geometry parameters of the above supercritical water reactor, and the calculation formula for the heat transfer enhancement correction factor; wherein the channel geometry parameters of the above supercritical water reactor include the channel length and the hydraulic diameter.

[0038] Optionally, the formula for calculating the above flow resistance correction factor is as follows:

[0039]

[0040] Where, ΔP total The total pressure drop is given above, f is the friction coefficient, L is the channel length, D is the hydraulic diameter, and K is... spacer ρ is the flow resistance correction factor, v is the fluid density, and v is the fluid velocity.

[0041] The formula for calculating the heat transfer enhancement correction factor is as follows:

[0042]

[0043] Among them, Nu corrected For the locally corrected Nusselt number mentioned above, Nu base Based on the Nusel number, C spacer The above-mentioned heat transfer enhancement correction factor is L, the above-mentioned channel length is D, and the above-mentioned hydraulic diameter is D.

[0044] Optionally, the steps of correcting the momentum conservation equation and energy conservation equation of the multi-channel model based on the flow resistance correction factor and the heat transfer enhancement correction factor to obtain the corrected multi-channel model include: establishing momentum correction terms and energy correction terms respectively based on the flow resistance correction factor and the heat transfer enhancement correction factor; embedding the momentum correction terms and energy correction terms into the momentum conservation equation and energy conservation equation of the multi-channel model respectively; and establishing the corrected multi-channel model based on the corrected momentum conservation equation and energy conservation equation.

[0045] Optionally, the above momentum correction term is -K. spacer ·v, where K spacer is the flow resistance correction factor mentioned above, and v is the fluid velocity.

[0046] Optionally, the above energy correction term is Among them, Nu base Based on the Nusel number, C spacer The above heat transfer enhancement correction factor is L, where L is the channel length and D is the hydraulic diameter.

[0047] Optionally, the steps for obtaining the multi-channel supercritical water reactor thermal model based on the modified multi-channel model and the local calculation results include: obtaining the calculation results of the modified multi-channel model, wherein the positional information of the calculation results of the modified multi-channel model corresponds to the positional information of the local calculation results; calculating the absolute value of the difference between the local calculation results and the calculation results of the modified multi-channel model; and iterating repeatedly until the absolute value is less than a preset threshold to obtain the multi-channel supercritical water reactor thermal model. It should be noted that the multi-channel simulation does not rely on a global correction factor; the influence of the positioning grid within each channel on flow and heat transfer behavior can be directly simulated using a local correction factor.

[0048] Optionally, the above method further includes: obtaining the number of channels and channel geometric parameters based on the above supercritical water reactor geometry and coolant flow path; establishing the above multi-channel model based on the above number of channels and the above channel geometric parameters, and initializing the above multi-channel model; the above initialization is to set the temperature, pressure, and flow velocity distribution in each channel of the above multi-channel model.

[0049] The multi-channel supercritical water reactor thermal analysis method based on positioning grid correction provided by the embodiments of the present invention has the following beneficial effects:

[0050] 1. Multi-channel calculations enable detailed simulation of flow and heat transfer behavior within each channel, particularly in the localized grid region, capturing complex local phenomena such as enhanced turbulence and localized heat transfer variations. Multi-channel calculations avoid the simplification issues of homogenization and provide higher local accuracy.

[0051] 2. Multichannel simulation methods are less dependent on geometric properties because they directly simulate the flow and heat transfer behavior within each channel, without relying heavily on domain partitioning and correction factors. Multichannel methods are more adaptable and flexible, better able to handle geometric complexity, and maintain high accuracy and computational efficiency even as model complexity increases.

[0052] 3. The multi-channel computation and structural fusion method enables tight coupling between global and local aspects. Through multi-channel simulation, the influence of the lattice can be directly reflected in the calculation of each channel without relying on a global correction factor, thus avoiding the limitations of global-local coupling and providing more consistent and realistic simulation results.

[0053] 4. Multi-channel simulation can dynamically reflect physical changes within each channel, including nonlinear effects induced by the positioning lattice. By embedding detailed simulation results of local structures into multi-channel calculations, the dynamic response and complex behavior of the positioning lattice region can be predicted more accurately.

[0054] 5. Multichannel computational methods can directly analyze the physical phenomena of global and local processes, including heat transfer and flow, as well as boundary condition variations in complex structures. Through detailed physical equations and dynamic solutions, multichannel computation can intuitively demonstrate and explain complex flow and heat transfer phenomena. This detailed process analysis helps engineers identify and understand potential problems and provides a clear physical basis for design optimization. Furthermore, multichannel models can perform parameter sensitivity analysis to clearly define the impact of lattice parameters (such as size, location, and shape) on flow and heat transfer, thereby providing higher interpretability and design optimization guidance.

[0055] The following embodiments detail a specific method for thermal analysis of multi-channel supercritical water reactors based on localized lattice correction. See also... Figure 2 The diagram shown is a schematic flowchart of a specific method for thermal analysis of a multi-channel supercritical water reactor based on localized grid correction. Figure 3 The schematic flowchart of the correction factor extraction method shown is as follows: Figure 4 The schematic flowchart shown is for the correction factor embedding method; it specifically includes the following steps:

[0056] Step 1: Based on the specific structure of the positioning grid in the supercritical water reactor, establish an accurate three-dimensional geometric model. This model needs to include the detailed structure of the positioning grid and the surrounding coolant flow region. Ensure that the model is sufficiently detailed, especially at key locations of the positioning grid, to accurately capture localized flow and heat transfer phenomena.

[0057] Step 2: Refine the mesh of the geometric model. Especially in the locating grid region, the mesh needs to be dense enough to accurately capture subtle phenomena such as turbulence and flow separation. Set appropriate boundary conditions for the CFD calculation, such as inlet velocity, outlet pressure, wall temperature, or adiabatic conditions.

[0058] Step 3: Use CFD software to numerically solve the constructed geometric model and mesh to calculate the flow velocity field, pressure field, and temperature field of the coolant in the positioning grid area.

[0059] Step 4: After obtaining the CFD calculation results, analyze the results to determine the changes in flow resistance and heat transfer coefficient, i.e., the influence of the positioning grid on local flow and heat transfer. The flow resistance correction factor is calculated using the flow resistance correction factor formula; the heat transfer enhancement correction factor is calculated using the heat transfer enhancement correction factor formula.

[0060] The formula for calculating the flow resistance correction factor is as follows:

[0061]

[0062] Where, ΔP total The total pressure drop represents the pressure loss of the fluid during flow due to friction and local resistance; f is the friction coefficient, describing the frictional effect between the fluid and the pipe wall, usually related to the Reynolds number (Re) and pipe roughness; L is the channel length; D is the hydraulic diameter; K spacer ρ is the flow resistance correction factor; v is the fluid density; v is the fluid velocity. The ratio of the channel length to the hydraulic diameter reflects the influence of the channel's geometry on the pressure drop.

[0063] The formula for calculating the heat transfer enhancement correction factor is as follows:

[0064]

[0065] Among them, Nu corrected Nu represents the locally corrected Nusselt number, characterizing the enhancement effect on heat transfer efficiency; base Based on the Nusselt number; C spacer is the heat transfer enhancement correction factor; L is the channel length; D is the hydraulic diameter.

[0066] Step 5: Based on the core geometry and coolant flow paths, divide the core into multiple independent coolant channels. Each channel corresponds to a flow path of the coolant within the core. Initial conditions are set, including the distribution of temperature, pressure, and flow rate. This step initializes the multi-channel calculations.

[0067] Step 6: Based on the correction factors extracted from the local CFD calculations, embed them into the momentum and energy conservation equations of the multi-channel model, respectively. This step ensures that the local effects of the positioning lattice are reflected in the global calculations.

[0068] The embedding of the flow resistance correction factor reflects the influence of the positioning grid on the flow resistance of the coolant, which is mainly reflected in the additional pressure drop when the coolant flows through the positioning grid. By constructing a momentum correction term and embedding the momentum correction term into the momentum conservation equation, the corrected momentum conservation equation is obtained.

[0069] The original momentum conservation equation is as follows:

[0070]

[0071] The revised momentum conservation equation is as follows:

[0072]

[0073] Where ρ is the fluid density; v is the fluid flow velocity; This represents the acceleration term of the fluid flow. is the pressure gradient, representing the change in pressure across a spatial location; μ is the dynamic viscosity of the fluid; The Laplace operator represents the fluid flow velocity; F represents the external body force; -K spacer •v is a momentum correction term used to increase additional flow resistance, which reduces the flow velocity in the channel and increases the pressure drop; the fluid mentioned above is a coolant.

[0074] The embedding of the heat transfer enhancement correction factor reflects the enhancing effect of the positioning grid on the coolant heat transfer coefficient, mainly due to the enhanced turbulence induced by the positioning grid, which improves heat transfer efficiency. In the energy conservation equation of the multi-channel calculation, an energy correction term is established based on the heat transfer enhancement correction factor, and this heat transfer energy correction term is embedded into the original heat transfer coefficient. Corrected heat transfer coefficient: in The revised energy conservation equation is obtained.

[0075] The original energy conservation equation is as follows:

[0076]

[0077] The revised energy conservation equation is as follows:

[0078]

[0079] Where ρ is the fluid density; c p is the specific heat capacity of the fluid; T is the temperature; k represents the thermal conductivity of the fluid; Q is the heat generated inside the system. This is the partial derivative of temperature with respect to time; The temperature gradient represents the change in temperature across spatial locations; the fluid mentioned above is a coolant.

[0080] Step 7: Through repeated iterations, calculate the results (temperature, pressure, flow rate, etc.) in each channel. When the relative rate of change of the above calculation results compared with the local calculation results is less than a preset threshold, the iteration converges.

[0081] Step 8: Integrate the final results of the multi-channel calculations to generate global calculation results (temperature field, pressure field, velocity field, etc.). Output the calculation results and compare them with the results without a positioning grid to evaluate the impact of the positioning grid on the overall core performance.

[0082] This invention proposes a specific method for multi-channel supercritical water reactor thermal analysis based on localized grid correction, specifically designed for accurate thermal calculations of supercritical water reactors. This method effectively couples global and local levels, accurately capturing the influence of the grid on coolant flow and heat transfer through multiple iterations. This enables high-precision simulation of complex flow and heat transfer phenomena within supercritical water reactors, offering advantages such as high accuracy, good dynamic response, strong interpretability, and high computational efficiency.

[0083] The existing methods have the following drawbacks: (1) The porous media model adopts homogenization, which cannot accurately capture the local influence of the positioning grid on flow and heat transfer, especially under complex phenomena such as enhanced turbulence and flow separation, the simulation accuracy is low. The inaccuracy of the porous media method in simulating the flow channel leads to difficulties in analyzing phenomena such as deterioration of heat transfer in rod bundles and flow-induced vibration. (2) When using the regional porous media method, the calculation method is highly dependent on the geometric characteristics of the model, and there is a relatively complex preprocessing stage, which is not scalable. As the complexity of the model increases, the limitations of the porous media method become more obvious, and it is difficult to meet the needs of high-precision thermal analysis. (3) The simulation accuracy of the local area of ​​the positioning grid depends on the accuracy of the correction factor. However, these correction factors are usually based on the simulation of the local positioning grid or empirical formulas, which cannot fully reflect the dynamic influence of the positioning grid on the overall flow and heat transfer distribution under different operating conditions. Especially under supercritical conditions, the nonlinear enhancement of flow and heat transfer makes the coupling between the global and local more complex, and the simple correction factor is difficult to accurately reflect the actual situation. (4) Due to its homogenization and simplification, the porous media method exhibits more pronounced nonlinear behavior (such as heat transfer deterioration and flow separation) in the location grid region under supercritical conditions. This method struggles to accurately predict these dynamic changes, especially under rapid changes in operating conditions or accidents, where the model's dynamic response capability is insufficient. (5) Through simplification and homogenization, the porous media method reduces complex geometric structures and physical phenomena to averaged parameters (such as permeability and heat transfer coefficient). This makes it difficult to intuitively understand and explain the specific details of fluid flow and heat transfer processes. Since these parameters are often obtained through empirical formulas or correction factors, they do not directly reflect specific physical phenomena and mechanisms. Therefore, it is difficult to derive a clear physical explanation or identify potential design improvement points when analyzing and diagnosing thermal problems.

[0084] In summary, the method of using porous media to integrate the positioning grid structure has the following drawbacks: inaccurate local simulation, strong geometric dependence, complex preprocessing, limitations in global and local calculations of critical points, and poor dynamic response. The method of using multi-channel calculation to integrate local simulation can better solve the above problems. The method provided by the embodiments of the present invention has the following advantages compared with the existing porous media integrated local simulation methods: (1) The embodiments of the present invention can more accurately capture the local influence of the positioning grid on flow and heat transfer by combining multi-channel calculation and local CFD simulation. This method avoids the homogenization treatment in porous media methods and can better reflect the actual physical phenomena, such as local turbulence enhancement and flow separation. (2) The embodiments of the present invention reduce the dependence on geometric structure, especially in the preprocessing of complex geometric structures, which does not require excessive simplification. This makes the model more flexible when facing designs of different complexities, and also reduces the workload of the preprocessing stage. (3) Multi-channel calculation can update the physical properties of the coolant (such as density, viscosity, etc.) in real time and dynamically reflect nonlinear changes, especially under supercritical conditions. This capability makes the method of the present invention more accurate and stable when dealing with complex working conditions and rapidly changing working conditions. (4) By directly embedding correction factors into the momentum conservation equation and energy conservation equation, this embodiment of the invention provides stronger physical interpretability. Engineers can clearly understand and analyze the impact of the positioning grid on flow resistance and heat transfer coefficient, thereby enabling more reasonable design optimization. (5) Compared with pure CFD simulation, this embodiment of the invention combines the global computing power of a multi-channel model with the refined processing of local simulation, significantly improving computational efficiency while ensuring computational accuracy. This is particularly important in large-scale core thermal analysis. (6) This embodiment of the invention can flexibly adjust the refinement of local simulation and the scope of global calculation according to requirements, making it not only applicable to the complex thermal analysis of supercritical water reactors, but also applicable to other types of reactor systems.

[0085] These advantages make the method of the present invention particularly advantageous in performing complex thermal analyses, especially in the design and optimization of supercritical water reactors.

[0086] The methods provided in this embodiment of the invention achieve the following functions and effects:

[0087] The method provided in this invention enables multi-scale thermal analysis of supercritical water reactors. First, it successfully achieves multi-scale coupled analysis from the microscopic (detailed flow and heat transfer characteristics of localized grids) to the macroscopic (flow and temperature distribution of the coolant throughout the reactor core). This method accurately captures physical phenomena at different scales within the supercritical water reactor, providing more precise and detailed thermal analysis results. Second, by embedding correction factors, this method reflects the impact of local structures on global flow and heat transfer, and continuously adjusts model parameters based on iterative results, achieving dynamic response analysis for different operating conditions. Third, by embedding explicit mathematical physics formulas (such as correction factors in the momentum and energy conservation equations), this method significantly enhances the physical interpretability of heat transfer and flow processes. Researchers can better understand and interpret the impact of local structures such as the grids on the overall reactor thermal performance, providing more robust design guidance. Finally, this method significantly improves computational efficiency while maintaining computational accuracy and reducing geometric dependence and preprocessing complexity. This makes the method more operational and flexible in practical engineering applications.

[0088] Furthermore, because the method provided in this invention enables multi-scale coupled analysis, researchers can further optimize core design in future studies and explore the impact of novel positioning lattice structures or other local designs on overall system performance. This will contribute to the development of efficient, stable, and safe supercritical water reactor systems. Through precise thermal analysis, heat transfer and flow processes within the reactor core can be better understood and optimized, supporting the design of more efficient nuclear energy systems. This method provides a scalable computational framework applicable to different types of reactor systems. Based on this, future research can further extend the method to the analysis of other complex thermal systems, exploring new local-global coupling strategies.

[0089] Of course, those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by computer-controlled devices. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above method embodiments. The storage medium can be a memory, a disk, an optical disk, etc.

[0090] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0092] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A multi-channel supercritical water reactor thermal analysis method based on positioning grid correction, characterized in that, The method includes the following steps: Based on the geometry of the supercritical water reactor and the coolant flow path, the number of channels and the channel geometry parameters are obtained; A multi-channel model is established based on the number of channels and the channel geometry parameters, and the multi-channel model is initialized; the initialization involves setting the temperature, pressure, and flow rate distribution in each channel of the multi-channel model. Based on the three-dimensional geometric model of the positioning grid and computational fluid dynamics, local calculation results are obtained. The three-dimensional geometric model of the positioning grid includes the positioning grid structure in each channel of the supercritical water reactor and the structure of the local coolant flow region near the positioning grid. Based on the local calculation results, the flow resistance correction factor and the heat transfer enhancement correction factor are obtained; The momentum conservation equation and energy conservation equation of the multi-channel model are corrected according to the flow resistance correction factor and the heat transfer enhancement correction factor to obtain the corrected multi-channel model. The position information of the momentum conservation equation and the energy conservation equation corresponds to the position information of the flow resistance correction factor and the heat transfer enhancement correction factor. Based on the modified multi-channel model and the local calculation results, a multi-channel supercritical water reactor thermal model is obtained. Acquire real-time nuclear reactor operating condition data under target supercritical conditions, including channel geometry parameters and coolant physical property parameters of the supercritical water reactor; The nuclear reactor operating data is input into the multi-channel supercritical water reactor thermal model to obtain global calculation results; Based on the global calculation results, an analysis was conducted to obtain an evaluation result of the impact of the positioning grid on the core performance under the target supercritical conditions; The process of obtaining the multi-channel supercritical water reactor thermal model based on the modified multi-channel model and the local calculation results includes: Obtain the calculation results of the modified multi-channel model, wherein the position information of the calculation results of the modified multi-channel model corresponds to the position information of the local calculation results; Calculate the absolute value of the difference between the local calculation result and the calculation result of the corrected multi-channel model; Through repeated iterations until the absolute value is less than a preset threshold, a multi-channel supercritical water reactor thermal model is obtained.

2. The method according to claim 1, characterized in that, The process of correcting the momentum and energy conservation equations of the multi-channel model based on the flow resistance correction factor and the heat transfer enhancement correction factor to obtain the corrected multi-channel model includes: Based on the flow resistance correction factor and the heat transfer enhancement correction factor, momentum correction term and energy correction term are established respectively; The momentum correction term and the energy correction term are respectively embedded into the momentum conservation equation and the energy conservation equation of the multi-channel model; Based on the modified momentum conservation equation and the modified energy conservation equation, a modified multi-channel model is established.

3. The method according to claim 2, characterized in that, The momentum correction term is ,in, This is the flow resistance correction factor. The fluid velocity.

4. The method according to claim 2, characterized in that, The energy correction term is ,in, Based on the Nusel number, This is the heat transfer enhancement correction factor. For channel length, It is the hydraulic diameter.

5. The method according to claim 1, characterized in that, The local calculation results obtained based on the three-dimensional geometric model of the positioning lattice and computational fluid dynamics include: The three-dimensional geometric model of the positioning grid was numerically solved using computational fluid dynamics software to obtain the flow velocity field, pressure field, and temperature field of the coolant in the positioning grid region. Based on the flow velocity field, the pressure field, and the temperature field, flow parameters and heat transfer parameters are obtained; wherein, the flow parameters include total pressure drop, friction coefficient, fluid density, and fluid velocity, and the heat transfer parameters include a locally corrected Nusselt number, which characterizes the heat transfer efficiency enhancement effect under the influence of the positioning grid.

6. The method according to claim 5, characterized in that, The process of obtaining the flow resistance correction factor and the heat transfer enhancement correction factor based on the local calculation results includes: The flow resistance correction factor is calculated based on the flow parameters, the channel geometry parameters of the supercritical water reactor, and the formula for calculating the flow resistance correction factor. The heat transfer enhancement correction factor is calculated based on the heat transfer parameters, the channel geometry parameters of the supercritical water reactor, and the heat transfer enhancement correction factor calculation formula. The channel geometry parameters of the supercritical water reactor include channel length and hydraulic diameter.

7. The method according to claim 6, characterized in that, The formula for calculating the flow resistance correction factor is as follows: ， in, The total pressure drop is mentioned. The friction coefficient is... The length of the channel. The hydraulic diameter is... This is the flow resistance correction factor. The fluid density is... The fluid velocity; The formula for calculating the heat transfer enhancement correction factor is as follows: ， in, This is the locally corrected Nusselt number. Based on the Nusel number, This is the heat transfer enhancement correction factor. The length of the channel. The hydraulic diameter is [value].

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