水泵水轮机在水轮机工况下转轮内不稳定流动及其演化

Unstable Flow and Evolution in the Runner in Turbine Operation of Pump-turbine

为了揭示水泵水轮机水轮机工况转轮内的不稳定流动及其演化过程,以模型混流式水泵水轮机为研究对象,对选定导叶开度下水轮机S特性区附近工况进行数值模拟研究,捕捉该开度下的转轮内不稳定流动并进一步揭示其产生机理。结果表明:沿等开度线,转轮内部出现了非定常涡以及旋转失速。其中,旋转失速表现出稳定的周期性特征,失速团造成通道严重阻塞,并以亚同步转速在叶片通道内传播。进一步分析表明,旋转失速由转轮内的非定常涡发展而来,涡结构发展造成的部分叶片通道阻塞促使了这一转化过程。

To reveal the unstable flow and its evolution process in the runner in turbine operation of pump-turbine,Taking the model pump-turbine as the research object,a numerical simulation study of the working conditions near the S characteristic zone of the turbine under the selected guide vane opening is carried out to capture the unstable flow in the runner under this opening and further reveal its generation mechanism.The results show that along the iso-opening line,unsteady vortices and rotating stalls appear inside the runner,which the rotating stall shows stable periodic characteristics,the stall causes serious blockage of the runner passage and propagates in the blade channel at a subsynchronous speed.Further analysis shows that the rotating stall is developed from the unsteady vortex in the runner,and the blockage of partial blade passage caused by the development of the vortex structure promotes this transformation process.