Load rejection is one of the most dangerous transients in pumped-storage plants, during which cavitation in pump-turbines is normally inevitable. In this study, we applied the one-dimensional and three-dimensional coupled computational fluid dynamics method to simulate the 100% load rejection transient process of a middle-head plant, analysed the evolution and influence of cavitation cavities, and evaluated the safety. During the guide-vane closing process, a spiral-shaped cavitation cavity under the runner cone and nine wedge-shaped cavitation cavities inside the blade channel outlets occur successively. Although no water column separation happens in the draft tube inlet, the collapses of the wedge-shaped cavities induce obvious impacts on the runner, causing axial force fluctuations, to which attention should be paid in the plant design phase. This study further validated the feasibility of the coupled method and revealed the mechanism of the dynamic cavitation phenomenon, which provides references for research and engineering design.

甩负荷是抽水蓄能电站中最危险的瞬变之一，在此期间，泵轮机中的气蚀通常是不可避免的。在这项研究中，我们应用一维和三维耦合计算流体动力学方法模拟了中封头工厂的 100% 甩负荷瞬态过程，分析了空穴的演变和影响，并评估了安全性。在导叶关闭过程中，转轮锥下的一个螺旋形空化腔和叶片通道出口内的九个楔形空化腔相继出现。虽然在尾水管入口处没有发生水柱分离，但楔形空腔的塌陷对转轮造成了明显的冲击，导致轴向力波动，在装置设计阶段应注意这一点。