不同攻角下水轮机导叶流道湍流特性研究

Turbulent Flow of Guide Vane under Different Attacking Angles

采用κ-ε湍流模型对不同导叶攻角下的导叶流道进行三维数值模拟,采用SIMPLEC算法实现速度、压力变量的分离求解。计算结果表明,导叶压力面的压力系数随着攻角增大而明显增大,而吸力面的压力系数随着攻角增大而明显减小。随着攻角增大,导叶边界层提前分离,形成脱落涡,导叶的升力明显增加。在导叶出水边的尾迹涡,其湍动能很大,随着流动进入转轮流道,引起水轮机水力振动。

3-D numerical simulation of flow around guide blade was performed using κ-ε turbulent model based on uncompressible fluid equation. SIMPIEC algorithm was applied to solve the coupled terms of velocity and pressure. The numerical results show that the pressure coefficient increases on the pressure side and that decreases on the suction side with attacking angles rising up gradually. The vortex come into being due to the boundary layer separating when attacking angles of the guide vane become larger. The vortex in trailing edge flows into the passage of the runner blade, which results in hydraulic vibration of Francis turbine.