水轮机固定导叶涡街的动力学分析与燕尾修型研究

The Analysis of Karman Vortex of Hydraulic Turbine Stay Vane Based on Vortex Dynamics and Study of Dovetail Modification

卡门涡的脱落与叶片尾部形状密切相关,为了研究固定导叶燕尾后缘对卡门涡脱落的影响,运用涡动力学理论对固定导叶涡量场进行分析,寻找涡街输运的一般规律;并对混流式水轮机的双列叶栅进行数值模拟,对原型和燕尾型固定导叶尾迹涡量场和压力脉动进行比较。数值计算结果表明:与原型相比,燕尾型固定导叶尾迹的涡量值和压力脉动相对减小。燕尾开叉角起到了延长涡街输运距离的作用,同时限制了新生漩涡的生长空间,降低了涡街能量;燕尾后缘对于卡门涡的脱落具有抑制作用,减弱了卡门涡的破坏能力。

The Karman vortex shedding is closely related to the shape of the trailing edge of vane. In order to study the effects of the dovetail trailing edge of stay vanes on vortex shedding, the vorticity field of the stay vane is analyzed in this article to find out the general rules of vortex motion by using vortex dynamics. Numerical simulation of Francis turbine＇ s tandem eascade is conducted with the vorticity field of the original and dovetail stay vanes and the pressure pulsations are then compared. The simulation results show that in comparison to the original vane, the vorticity value and pressure pulsation of the dovetail stay vane wake are relatively less. The split angle extends the vortex motion distance, limits the growth space of new vortexes and lowers the energy of vortexes. The dovetail trailing edge of the stay vane has an inhibitory effect on vortex shedding, which weakens the damage capability of vortexes.