导叶端面间隙泥沙磨损数值预测研究

高水头混流式水轮机导叶间隙是泥沙磨损破坏最为严重的部分之一。泥沙磨损破坏问题与固液两相流动特征关系密切,为了揭示导叶端面间隙内含沙水的流动规律,本文应用固液两相流模型,通过求解雷诺时均N-S方程和RNG k-ε湍流方程,对泥沙介质条件下水轮机导叶端面间隙流动进行数值研究。研究结果表明,含沙水在压差的驱动下从导叶间隙的压力侧向吸力侧方向流动,间隙内部泥沙浓度低于主流;导叶间隙尺度增大会导致间隙内部含沙水速度增加,含沙水对导叶的磨损强度增大。

Numerical Study on Solid-liquid Two-phase Flow in Francis Turbine Runner

The end clearance of guide vanes is one of the most serious parts of sediment erosion damage for high head Francis turbine.The problem of sediment erosion damage is closely related to solid-liquid two-phase flow characteristics.In order to reveal the flow laws of sandy water in the end clearance of guide vane,the solid-liquid two-phase model is applied to numerically study the flow under the sandy condition by solving the Reynolds averaged Navier-Stokes equations and RNG k-ε turbulence equations in this paper.The results indicate that pressure difference makes sandy water flow from pressure to suction sides of guide vane clearance.Sediment concentration in the clearance is less than mainstream's ones.Scale increase of guide vane clearance will increase sandy water velocity in the guide vane clearance,and also increase sandy water's wear strength.