Abstract Pumped storage technology has become the most important energy storage technology in industry today. The instabilities of pump-turbines as key parts of pumped storage power plants have become critical issues in development of pump storage technology. High-amplitude pressure fluctuations are one of such instabilities. In this study, unsteady numerical simulations were carried out in the pump mode of a pump-turbine at using the shear stress transport (SST) k-ω turbulence model. Performance characteristics agree well with experimental data. Unsteady characteristics of typical operating points were obtained. The results show that there are high-amplitude pressure fluctuations at the partial operating points. The frequency characteristics and the propagation law of an at-large partial operating point (0.74QBEP) were determined using time and frequency domain analysis methods (bispectrum, coherence) in combination with the flow field. The analysis results reveal that high-amplitude pressure fluctuations at point 0.74QBEP result from the rotation of Dean Vortices in the draft tube. Due to the rotation of the Dean Vortices, the blocking intensity of the two regions in the guide vane and the stay vane passages are periodically changed at a frequency 0.58fn, which results in a shock phenomenon in the guide/stay vanes.

中文翻译：

---

泵模式下泵轮机中高幅低频波动的机理

摘要 抽水蓄能技术已成为当今工业上最重要的储能技术。作为抽水蓄能电站关键部件的水泵水轮机的不稳定性已成为抽水蓄能技术发展的关键问题。高振幅压力波动就是这种不稳定性之一。在这项研究中，使用剪切应力传输 (SST) k-ω 湍流模型在泵 - 涡轮的泵模式下进行非定常数值模拟。性能特征与实验数据非常吻合。获得了典型工作点的非稳态特性。结果表明，在部分工作点处存在高幅度的压力波动。大局部工作点 (0. 74QBEP）是使用时域和频域分析方法（双谱、相干性）结合流场确定的。分析结果表明，0.74QBEP 点处的高振幅压力波动是由Dean Vortices 在引流管中的旋转引起的。由于迪安涡旋的旋转，导叶和撑叶通道两个区域的阻塞强度以0.58fn的频率周期性变化，导致导/撑叶出现震荡现象。