导叶头部圆半径对水泵水轮机水力特性的影响

Influence of radius of guide vane head on hydraulic performance of pump-turbine

针对水泵水轮机“S”特性,以国内某抽水蓄能电站水泵水轮机模型机为研究对象,改进活动导叶翼型几何结构,基于Realizable k-ε湍流模型,通过数值计算分析改进活动导叶翼型几何结构对水泵水轮机“S”特性的改善及水力性能的影响.结果表明:减小导叶头部圆半径r至r-0.313 mm,对机组“S”特性存在较佳的改善效果,主要是由于减少了导叶出口及转轮进口等处的旋涡,改善了转轮叶片进口旋涡流阻塞通道的情况;随着r减小,转轮所受径向激励力合力呈先减小后增大趋势,且在r-0.313 mm时转轮径向力合力最小,径向力合力的峰谷差值最小,对应的转轮径向力合力也较稳定,对机组的运行影响较小,结合效率总结出方案r-0.313 mm是6种方案中的最优方案;分析飞逸工况下S1流面流态及无叶区压力脉动可得方案r-0.313mm对应的活动导叶出口端的高压区域最少,整体来看无叶区压力脉动曲线变化有一定的周期性.

Aiming at the “S” characteristic of the pump-turbine,a pump-turbine model of a domestic pumped-storage power station was used as the research object and improved the geometry of the guide vane airfoil.Based on the Realizable k-ε turbulence model,the improvement of the geometry of the guide vane airfoil on the amelioration of the “S” characteristic and the hydraulic performance of the pump-turbine was discussed through numerical calculations.The results show that reducing the head radius r to r-0.313 mm has a better effect on the“S”characteristic of the pump-turbine,mainly due to the reduction of the vortex at the guide vane outlet and the entrance of the runner,etc.,improving the situation that the vortex flow at the entrance of the runner blades blocks the passage.As r decreases,the total radial excitation force on the runner first decreases and then increases.And at r-0.313 mm,the total radial force of the runner is the smallest,the peak-valley difference of the total radial force is the smallest,the corresponding total radial force of the runner is also relatively stable,which has little impact on the operation of the pump-turbine.Combined with the efficiency,it is concluded that the solution r-0.313 mm is the optimal solution among the 6 schemes.Analyzing the flow pattern of the flow surface in the runaway condition S1 and the pressure pulsation in vaneless area,the high pressure area at the outlet of the guide vane corresponding to the scheme r-0.313 mm should be the least. On the whole,the pressure fluctuation curve of the vaneless area has a certain periodicity.