液态铅铋横向流作用下单棒流致振动特性数值研究
Numerical Study on Vibration Characteristics of Single Rod Suffered Liquid Lead-Bismuth Cross-Flow

铅铋堆中的液态铅铋金属流体与常规介质物性差异较大，其流致振动特性需要明确。针对反应堆中的圆柱横向流致振动，本文对单棒在不同铅铋来流工况下流致振动特性进行了数值研究。首先通过悬臂棒的理论固有频率验证了模态分析的正确性，通过模态分析获得单棒在空气和铅铋中的固有属性。然后采用流固耦合仿真计算开展不同工况下的铅铋流质中单棒流致振动特性研究。结果表明铅铋绕流固定单棒时漩涡脱落频率对应的斯特劳哈尔数为0.2，与经典单圆柱绕流斯特劳哈尔数一致。对于与流体有耦合的弹性棒，当入口流速和温度恒定时，受铅铋流体冲击，棒先发生脉动幅值较小的静变形，然后逐渐稳定地脱落漩涡，使得振幅逐渐增大。
The physical properties of liquid lead-bismuth metal fluid in lead-bismuth reactor are quite different from those of conventional medium, and its fluid-induced vibration characteristics need to be clarified. For the cross-flow induced vibration in reactor, the vibration characteristics of a single rod suffered different lead-bismuth cross-flow conditions are studied numerically in this paper. Firstly, the theoretical natural frequency of the cantilever rod is used to verify the correctness of the modal analysis, and the natural properties of the single rod in air and lead bismuth are obtained by modal analysis. Then the single rod fluid-induced vibration in lead-bismuth fluid under different working conditions was studied by fluid-structure coupling simulation. Results show that the Strouhal number corresponding to the vortex shedding frequency is 0.2, which is consistent with that of classical flow around the circular cylinder. For the elastic rod coupled with the fluid, when the inlet velocity and temperature are constant, the rod is impacted by the lead-bismuth fluid, and the static deformation with small fluctuation amplitude occurs first, and then the vibration amplitude increases gradually because of the steady vortex shedding.