RELAP5/FLUENT耦合程序的开发

热工水力数值模拟是反应堆系统设计和安全分析的重要内容，以RELAP5为代表的系统程序可对瞬态或事故工况进行快速分析，同时以FLUENT为代表的计算流体动力学(CFD)程序对堆芯局部三维现象的分析也越来越重要。为综合利用两者的优点，以RELAP5/FLUENT为基础，利用对RELAP5程序源代码的二次开发和FLUENT的用户自定义函数(UDF)进行编程，开发了RELAP5/FLUENT耦合程序。利用flibe熔盐在水平圆管流动问题验证了程序耦合的正确性；针对2 MW熔盐堆进行了稳态模拟，耦合程序能详细分析熔盐堆的热工水力行为；模拟了2 MW熔盐堆功率突变的瞬态热工水力行为，相对于单独的RELAP5，耦合程序能更好地揭示熔盐堆系统和堆芯的三维物理现象。该耦合程序可用于解决熔盐堆热工水力分析中存在的显著三维混合现象的问题。

Development of Coupled Program Based on RELAP5/FLUENT

Thermal-hydraulic simulation analysis is an important part of reactor system design and safety analysis. The system program represented by RELAP5 can quickly analyze transient or accident conditions. Meanwhile, the computational fluid dynamics (CFD) code represented by FLUENT analyzing local 3D phenomena is also increasingly important. In order to make full use of the advantages of both, a RELAP5/FLUENT coupled program was developed by the secondary development of the RELAP5 source code and FLUENT UDF. The coupled program was verified by using the problem of flibe molten salt flowing in a horizontal pipe. A steady-state simulation was performed for the 2 MW molten salt reactor, and the coupled program can analyze the physical phenomenon of the molten salt reactor core in detail. Finally, the transient thermal-hydraulic behavior of a 2 MW molten salt reactor with an abrupt power was simulated. Compared with the RELAP5, the coupled program can better reveal the physical phenomenon of the molten salt reactor core. This coupled program can be used to solve the problem of some significant three-dimensional mixing phenomenon in the thermal-hydraulic analysis of molten salt reactor.