燃料组件典型栅元湍流激振数值研究

为掌握全长范围内的燃料棒振动响应特性，以用于燃料棒微动磨损寿命分析，本研究运用计算流体动力学（CFD）方法，对燃料组件典型栅元的湍流激振进行数值模拟分析，并通过棒表面的瞬态脉动压力分布开展不同夹持力下的单棒瞬态动力学分析。研究表明:格架上游的截面平均湍动能约为0.1 m2/s2，格架临近出口位置湍动能达到峰值的0.65 m2/s2，格架的存在显著增强了流场的湍流强度，这是造成燃料棒湍流激振的主要原因；通过瞬态动力学分析确定了均方根振幅最大的定位格架位置，并建立了该格架的均方根振幅和振动速度随夹持力变化的关联式。本研究将为后续微动磨损理论计算及实验验证奠定基础。 

Numerical Study on Typical Cell of Fuel Assembly by Turbulence Excitation

In order to master the vibration response characteristics of fuel rods in the full length range for fretting wear life analysis of fuel rods, this study is to use the computational fluid dynamics (CFD) method to numerically simulate the turbulence excitation of typical lattice of fuel assembly, and to carry out the transient dynamic analysis of a single rod under different clamping forces through the transient fluctuating pressure distribution on the surface of fuel rod. The results show that: the average turbulent kinetic energy of the upstream section of the grid is about 0.1 m2/s2, and the turbulent kinetic energy peaks at 0.65 m2/s2 near the grid outlet. Therefore, the existence of grid significantly enhances the turbulence intensity of the flow field, which is the main reason for the turbulence excitation of the fuel rod; the position of the spacer grid with the maximum root mean square amplitude is determined by transient dynamic analysis, and the correlation between the root mean square amplitude and vibration velocity of the grid with the clamping force is established. This study will lay a foundation for the following theoretical calculation and experimental verification of fretting wear.