基于OpenFOAM的液态金属铅铋三维流动换热特性数值模拟研究

铅铋快堆是第4代核能系统的主要堆型之一，但由于液态金属铅铋的热物性与传统工质如水、空气等有很大不同，假设流动边界层与热边界层相似的雷诺比拟原理已不再适用。本文在开源程序OpenFOAM中开发了基于k-ε-k_θ-ε_θ四因子模型的自定义求解器，考虑热边界层与流动边界层的差异性，对带绕丝棒束通道中液态金属铅铋的流动换热现象进行数值模拟，得到了速度、温度等重要热工水力参数的三维分布，揭示了绕丝对冷却剂流动传热过程的影响规律，并将计算结果与经典实验关联式进行对比，结果符合良好，证明了所用模型和程序的正确性。本研究可为在OpenFOAM中添加新模型、开发自定义求解器以及开展针对液态金属流动换热问题的计算流体动力学（CFD）模拟提供参考。

Numerical Simulation of Three-dimensional Flow Heat Transfer Characteristics of Liquid Lead-bismuth Using OpenFOAM

Liquid metal reactor is one of the main types of the Gen-Ⅳ nuclear power system. However, because the thermal properties of liquid lead-bismuth are very different from those of traditional working media such as water and air, the Reynolds analogy principle, which assumes that the flow boundary layer is similar to the thermal boundary layer, is no longer suitable. In this paper, a custom solver based on k-ε-k_θ-ε_θ four-parameter model was developed in open source program OpenFOAM. The difference between the thermal boundary layer and the flow boundary layer was considered. The flow heat transfer simulation of liquid lead-bismuth in a wire-wrapped rod bundle was carried out. The three-dimensional distribution of some important thermal hydraulic parameters such as velocity and temperature was obtained. The influence of wire on the flow and heat transfer process of coolant was revealed, and the calculated results were compared with the classical experimental correlations. The results are in good agreement, which indicates the correctness of the model and program. This study may provide references for CFD simulations of liquid metals flow and heat transfer by adding new models and developing custom solvers in OpenFOAM.