Large-Scale Thermo-Hydraulic Analysis of Fuel Rod Bundles Based on YH-ACT

In the design process of nuclear reactors, high-fidelity numerical simulations of thermo-hydraulic processes play a crucial role in evaluating the feasibility and safety of design schemes. These simulations involve complex physical processes such as coolant flow, thermal conduction, and heat transfer, necessitating the use of high-precision numerical algorithms and efficient parallel optimization methods. While mainstream commercial software is widely used in reactor design, it often falls short when it comes to meeting customized experimental scenarios and faces limitations in parallel scalability and physical model adaptability. Hence, the development of independent thermo-hydraulic parallel applications becomes essential. This paper focuses on conducting large-scale refined thermo-hydraulic analysis of core fuel rod bundles using the self-developed software YHACT. The paper elucidates the model algorithm design, parallel implementation, and analysis of test results. Two typical cases were selected for verification by comparing the obtained results with those from FLUENT. Emphasis was placed on the large-scale parallel simulation of fluid-solid coupled convection heat transfer phenomena between fuel rod bundles, utilizing a mesh scale exceeding 100 million cells. This breakthrough overcomes the scale limitations encountered with commercial software, and promises to foster further research and development in related fields.