水泵水轮机导叶卡门涡数值模拟研究

摘要

Karman vortex phenomenon near downstream side ofwicket gateof pump turbineis simulatedunder different operating condition, by using numerical simulation method.Vorticity distribution, flow condition ofKarman vortex, and flow separation behind wicket gate are revealed. Velocity curve of monitoring point andcurve offorceon wicket gate perpendicular to flow directionare obtained,andKarman vortex frequencyofwicket gate under turbine and pump operating condition are 84.9Hz and 53.3Hzrespectively.It is proved thatKarman vortex frequency obtained by usingtheoretical formula for flow around circular cylinderis not accurate, while numerical simulationmethodhashigheraccuracy.The research shows great significanceinpump turbine wicket gate designand avoiding vibration induced by Karman vortex.%利用数值模拟方法,模拟水泵水轮机不同工况下,导叶出水边的卡门涡现象,揭示导叶下游侧流场涡量分布、导叶出水边附近卡门涡流动状态和流场脱流等.提取监测点速度变化曲线和导叶壁面垂直流向合力变化曲线,通过数据处理,获得水轮机工况和水泵工况,导叶出水边卡门涡频率分别是84.9Hz和53.3Hz.通过对比分析,证明利用经验公式计算得到的卡门涡频率存在较大误差,而数值模拟方法具有较高计算精度.研究结果对水泵水轮机导叶设计、避免发生卡门涡共振问题具有一定指导意义.