针对中低比转速水轮机空化、振动问题比较突出的现象,以大桥电站水轮机为例,采用分离涡模型(DES)对其进行了三维CFD计算,得到了活动导叶、转轮和尾水管内的压力分布、速度分布及压力脉动特性。结果表明,转轮空化发生在叶片出水边靠近下环的区域,与实际情况相符;机组在高水头、大开度工况下,振动更突出,振动频率为机组旋转频率的整数倍,表明振动主要由转轮造成,而非尾水管涡带引起的。 In view of the phenomenon of cavitation and vibration of medium and low speed turbine, the turbine of Daqiao Hydropower Station is taken as an example. The three-dimensional CFD calculation is carried out by the separation vortex model (DES), and the moving vanes, runner and draft tube are obtained Pressure distribution, velocity distribution and pressure pulsation characteristics. The results show that the rotor cavitation occurs in the area near the lower ring when the water outflows from the blade, which agrees with the actual situation. Under the condition of high water head and large opening, the vibration is more prominent and the vibration frequency is an integral multiple of the rotating frequency of the unit Vibration is mainly caused by the runner, not caused by the draft tube vortex.