【摘要】 系统分析程序与计算流体动力学（Computational Fluid Dynamics,CFD）程序的耦合模拟是数值反应堆研究中的关键技术，结合两者优势可实现多尺度的高精度、快速仿真，满足全局效应分析和局部细节捕捉的需求。基于系统程序（Nuclear Safety and Operation Laboratory-System,NUSOL-SYS）与CFD程序FLUENT，开发了一种分解域的半隐式压力修正迭代耦合方法。该方法通过在耦合边界上设定相同压力，利用敏感性关系矩阵结合边界质量流量差逐步调整压力，实现收敛。基于单管流动问题和并联流动问题验证收敛性和可靠性后，将该工具应用于ACP100模块化小型压水堆主泵停转事故的堆芯入口流量分布分析，结果表明：事故发生后堆芯入口流量分配未出现不均匀现象，耦合程序计算得到的系统参数与NUSOL-SYS单独计算结果基本一致，且能捕捉局部三维流动特征。该方法为核动力系统热工水力的多尺度模拟提供了参考价值。更多还原

【Abstract】 [Background] The coupled simulation of system analysis codes and computational fluid dynamics(CFD) code is a key technical approach in numerical reactor research. This coupling method combines the advantages of both codes to achieve high-precision, rapid multi-scale simulations. It addresses the requirements for global effect analysis while accurately capturing detailed phenomena in critical regions, thus providing precise support for reactor design optimization and safety evaluation. [Purpose] This study aims to develop a domain-decomposition-based semi-implicit one-dimensional-three-dimensional pressure correction iterative coupling method, integrating the commercial CFD code FLUENT with the system analysis code Nuclear Safety and Operation Laboratory-System(NUSOL-SYS). [Methods] Firstly, the consistent pressure values at the coupling boundary was initialized to establish a sensitivity matrix between pressure and mass flow rate differences by iteratively adjusting the boundary pressure. Then the coupling pressure correction was calculated by incorporating the mass flow rate differences across the boundary at the current iteration step, and the coupling boundary pressure was continuously corrected to ensure mass flow rate consistency on both sides during the iteration process, thereby achieving convergence and advancing the time step. Subsequently, this coupling method was applied to calculating single-pipe flow problem, and further validated by simulating a parallel flow problem with varying time steps and flow channels. Finally, the coupled code was employed to analyze the core inlet flow distribution during a main coolant pump trip scenario in the ACP100, a modular small pressurized water reactor. [Results] The coupling calculation results for the single-pipe flow problem show a high consistency with the results of NUSOL-SYS standalone calculations, and convergence is achieved within two iterations. Validation results demonstrate that the coupling program reduces the mass flow residual by 1 to 3 orders of magnitude in each iteration under different conditions. Analysis results on ACP100 main coolant pump trip scenario indicate that no uneven flow distribution occurs at the core inlet following the accident. Moreover, the system parameters predicted by the coupled code are consistent with those obtained from standalone NUSOL-SYS simulations, while the code also successfully captures localized three-dimensional flow phenomena. [Conclusions] The semi-implicit iterative coupling method proposed in this study demonstrates good stability and convergence, providing a scientific approach for optimizing reactor component design and enhancing system accident resistance, while laying an important foundation for the further development of numerical reactors.更多还原