水泵水轮机尾水管压力脉动特性及涡带特性分析

Analysis of Pressure Pulsation Characteristics and Vortex Band Characteristics ofDraft Pipe of Pump Turbine

抽蓄电站是电网的重要组成部分,水泵水轮机长时间偏离最优工况运行会导致水力不稳定问题,其中,尾水管涡带和压力脉动问题备受关注,严重影响机组安全稳定运行。以水泵水轮机为研究对象,分析了其尾水管内流特性与压力脉动时频特性。对比了两种第二代和两种第三代涡识别方法对尾水管涡带演化过程的可视化效果,Omega-Liutex涡识别方法对阈值依赖性小且对涡带形态的识别更清晰完备,因此,采用Omega-Liutex涡识别方法研究了不同负荷工况下尾水管涡带的瞬态变化特性。研究结果可以为水泵水轮机稳定运行提供一定的理论参考。

The pumped storage power station is an important part of the power grid,and the long time deviation of the pump turbine from the optimal operating condition will lead to hydraulic instability problems,among which the vortex band and pressure fluctuation of the draft tube are concerned,which seriously affects the safe and stable operation of the unit.Taking pump-turbine as the research object,the characteris⁃tics of the flow in the draft pipe and the time-frequency characteristics of pressure pulsation are analyzed in this paper.The visualization ef⁃fects of two second-generation vortex identification methods and two third-generation vortex identification methods on the evolution process of draft tube vortex zone are compared.The Omega-Liutex vortex identification method has less dependence on threshold value and is more clear and complete in recognizing the shape of vortex zone.Therefore,the transient change characteristics of draft tube vortex zone under dif⁃ferent load conditions are studied by using the Omega-Liutex vortex identification method.The research results can provide some theoretical reference for the stable operation of pump turbines.