压水堆燃料棒在轴向流作用下的随机振动响应研究

基于随机振动理论,建立了在轴向流作用下压水堆燃料棒随机响应的纯理论分析方法。将流体力考虑为沿燃料棒轴向位置的脉冲随机荷载,结合模态分析技术,从功率谱分析法推导出燃料棒振动均方根响应的表达式。提供了一套不依赖燃料组件流致振动实验的纯理论分析方法,重点分析了等效流速、湍流强度、相关长度系数等几个主要流场参数对结构均方根响应的影响。结果表明,本文计算模型的精度满足工程分析要求,燃料棒响应随等效流速、湍流强度和相关长度系数的增大而增大;其中响应对于等效流速和相关长度系数的变化较为敏感,而与湍流强度呈线性变化关系;在压水堆运行中的燃料棒均方根幅值约处在μm量级。

Random Response Analysis of PWR Fuel Rod Effect on Axial Flow

Based on random vibration theory, the random response analysis method of PWR fuel rods under axial flow was established. The fluid force along the axial of rod was treated as a fluctuant random load, and the mode shape method and power spectrum analysis method were used to derive the empirical formula of RMS response. This article provides a theoretical analysis method which does not rely on the flow induced vibration test of fuel assembly. The effects for the RMS response of fuel rods by the equivalent velocity, turbulence intensity, and correlation length factor were discussed. The method can meet the requirements of engineering analysis. The results show that the RMS response of fuel rods will increase with the equivalent velocity, turbulence intensity and the correlation length factor. The response is more sensitive to the equivalent velocity and coefficient length factor changes, and linearly with the turbulence intensity. In the operating condition of the pressurized water reactor (PWR), the RMS amplitude of fuel rods is about micrometers.