基于脱体涡模型的竖井贯流式水轮机组压力脉动数值分析

摘要

Three-dimensional unsteady eddy numerical simulations are carried out for the hydraulic performances of the pit turbine unit of a tidal power station by using the detached-eddy model based on the CFD method.The pressure pulsation information at key measuring points located in the passage under different water heads is obtained and analyzed.The results show that all the pressure pulsation in the whole passage of the tidal pit turbine contains rotation frequency,and the nearer the distance to the runner is,the larger is the amplitude of the rotation frequency.The pressure pulsation at the runner chamber is strong,and its amplitude increases with the increase of water heads.The predominant frequency is the rotation frequency with three and six times.The pressure pulsation at the inlet side of guide vanes and the outlet conduit is weak and its frequency is low.Change of the water head has a little effect on the pressure pulsation at the inlet side of guide vanes.The flow regime in the outlet conduit is the best under the design condition,and the pressure pulsation is the smallest.%应用基于CFD方法建立的脱体涡模型对某潮汐电站竖井贯流式水轮机组的水力特性开展全流道三维非定常湍流数值模拟,获取不同水头工况下流道内关键位置处测点的压力脉动信息.结果表明:该潮汐竖井贯流式水轮机组流道内压力脉动均含有转频分量,距离转轮越近,转频分量幅值越大；转轮段压力脉动较强,振幅随水头的增加而增大,频率以3倍和6倍转频为主；导叶进水侧和出水流道内压力脉动较弱,且以低频分量为主；水头变化对导叶进水侧压力脉动影响很小；出水流道在设计工况下流态最好,压力脉动最小.