中文摘要：

旋转失速是一种会显著降低水泵性能的不稳定流动现象。为研究离心泵旋转失速团的特性,采用动态混合非线性SGS模型对一离心泵叶轮进行了大涡模拟,得到了泵内部失速流场和压力脉动特性。研究发现,对于所研究的叶轮来讲,叶轮失速频率为转频的24%,叶轮内存在3个失速团,失速团的转速为叶轮转速的8%。对不同时间的内部流场进行分析,可以看到失速团首先产生于叶片吸力面,并逐渐增大,几乎阻塞了整个流道,导致顺着叶轮旋转方向的相邻叶片的进口冲角减小,该通道过流能力提高,退出阻塞状态;而在逆叶轮旋转方向的相邻叶片的进口冲角增大,通流能力减弱,直到流场也发生阻塞。按照这种传播规律,失速团在叶轮流道内以8%的叶轮转速缓慢传播。

英文摘要：

Rotating stall is an unsteady flow phenomenon that always causes instabilities and low efficiency in pumps. The purpose of this paper is to investigate the features of rotating stall flow in a centrifugal pump impeller based on a dynamic mixed nonlinear model （DMNM） combined with large eddy simulation method. The internal flow field and pressure fluctuation characteristics at the stall point are obtained. The simulation results show that the number of stall cells is 3 and the stall frequency is 2.44 Hz. Furthermore, the internal flow field of the impeller at different times during the stall cycles is presented. The stall cells are firstly occurred in the suction side of the blades. Then the area occupied by stall ceils gradually in- creases until almost blocking the inlet section, forcing the flow turn to adjacent passage in the rotating di- rection of the impeller, which leads to a decreased angle of incidences on the blade. However, the other adjacent channel experiences an increased angle of incidences and the stall cell turns up. According to this rule, the stall cells propagate at 8 % of rotor speed in the impeller.