基于CFD方法的铅铋冷却燃料棒束的热工水力特性分析

铅铋冷却快堆作为第4代反应堆候选之一具有安全性高等特点，研究其在正常工况下的热工水力特性具有重要意义。本文基于商用计算流体力学（CFD）软件STAR-CCM+，使用流固耦合的方法对带有绕丝结构的19棒束铅铋组件进行数值分析，探究了质量流量、功率等边界条件对组件内部流动传热特性的影响。模拟计算结果表明：CFD方法在子通道中心温度和壁面温度预测上与实验结果取得了较好的一致。同时，绕丝结构的存在使得子通道之间存在周期性的横向交混，并使得棒束表面温度呈现震荡。随质量流量的增加，子通道间横向交混增大。功率变化对通道间的横向交混速度的影响较小，冷却剂温度的横向分布无明显差异。

Thermal Hydraulic Analysis of LBE-cooled Rod Bundle Based on CFD Method

LBE-cooled fast reactor (LFR) as one of the candidates of generation Ⅳ nuclear systems has the characteristics of high security. It is significance to study the thermal hydraulic characteristics under normal conditions. The commercial computational fluid dynamics software STAR-CCM+ was used to simulate the 19-bundle lead-bismuth assembly with wire-wrap by fluid-solid interaction. And it was studied on the influence of boundary conditions such as mass flow rate and total power on the internal heat transfer characteristics of the assemblies. The simulation results show that the simulation results are in good agreement with experiment results in the prediction of the temperature of sub-channel center and wall temperature. At the same time, the wire-wrap structure leads to the periodic cross mixing between the sub-channels and makes the surface temperature of rod bundle oscillate. When mass flow rate increases, the cross mixing velocity between sub-channels increases. The power change has less effect on the cross mixing between the channels, and there is no significant difference in the coolant temperature distribution.