【摘要】 流弹稳定性和漩涡脱落是流致振动分析的两个重要机理。由于制造工艺、运输、辐照影响,格架对燃料棒的夹持作用可能失效。以I、II型燃料组件为例,研究了夹持失效对燃料棒固有频率和振型、流弹稳定性以及漩涡脱落的影响。结果表明:刚凸支承失效对固有频率的影响与振型有直接关系,原振幅较大的位置附近刚凸支承失效对固有频率的影响明显。刚凸支承失效对两种型号燃料棒固有频率的影响类似。对于I型组件,燃料棒顶部和底部的流速较大,大小相当,顶部和底部格架的刚凸支承失效对流弹稳定性及漩涡脱落比值有较大影响。对于II型组件,顶部格架刚凸支承失效对流弹稳定性及漩涡脱落比值的影响明显。更多还原

【Abstract】 Flow elastic stability and vortex shedding were two important mechanisms for the flow induced vibration analysis. Due to the effects of manufacturing process, transportation and irradiation, the clamping action of grid on fuel rods may be invalid. Taking Type I and II fuel assemblies as an example, the effects of clamping failure on the natural frequencies, mode shapes, flow elastic stability and vortex shedding were studied. The results show that the effect of the dimple support failure on the natural frequency was directly related to the mode shape. The effect of the grid dimple failure near the original amplitude on the natural frequency was obvious. The effect of dimple failure on the natural frequency of two fuel rods was similar. For Type I, the velocity of flow at the top and bottom of the fuel rods were larger and the size was comparable. The dimple failure of the top and bottom grids had a significant effect on the stability of flow elastic and the vortex shedding ratio. For Type II fuel assembly, the dimple failure of the top grids had a more significant effect on the stability of flow elastic and the vortex shedding ratio comparing to the bottom grid failure.更多还原