不同比例长短叶片对混流式水轮机内部流场的影响

The Influence of the Internal Flow Field on Francis Turbine with Different Proportions of Long and Short Blades

为探究不同比例长短叶片对混流式水轮机各过流部件内部流场的影响,采用RNGk-ε湍流模型和三维时均N-S方程,对不同比例长短叶片混流式水轮机进行全流道三维定常数值模拟。计算结果表明在不影响转轮区流态的情况下,适当增加短叶片长度,水轮机抗空化空蚀性能有所提高,尾水管进口低压区覆盖面积有所减小。但随着短叶片长度的增长,水轮机效率降低,且固定导叶尾部、活动导叶头部以及蜗壳鼻端高压覆盖面积增大。以上结论对长短叶片混流式水轮机的设计、优化和改型等研究具有一定的指导意义。

In order to gain the influence on internal flow of Francis turbine by different proportions of long and short blades. The RNGk-ε model and the Reynolds average Navier-Stokes equations are used to carry out the 3D turbulent numerical simulation re- search on the Francis turbine with different proportions of long and short blades. The results are compared with the Francis turbine with different proportions of long and short blades. It shows that increasing the length of short blade can improve the cavitation re- sistance in the case of not influencing the flow of the runner area. And it can also reduce the area of the low pressure area of the draft tube. However, with the increase length of short blades, turbine efficiency includes reduction, and the area of the high pressure in the outlet of fixed guide vanes, the inlet of movable guide vanes and the tongue of volute increase. In short, these conclusions are of great significance to the design, optimization and modification of Francis turbine with long and short blades.