Computational Research on the Formation Mechanism of Rotating Stall Induced by Rotor Stator Interaction in a Pump-Turbine Under Pump Mode

Rotating stall is an abnormal flow phenomenon in pumps and pump-turbines, which can cause severe vibration, noise, and even cause head hump. A pump-turbine model under pump mode is researched in this study to reveal the formation mechanism of rotating stall. The causes, development laws, and influencing factors of rotating stall is revealed, which can help professionals achieve a deeper understanding of the rotating stall mechanism and suppress it through optimized design. The flow simulation method is mainly adopted in the study, and it is verified through experiment. The research results show that stall in the guide vanes is often caused, maintained and aggravated by rotor–stator interaction (RSI). A stall cell is often difficult to cause the adjacent flow channel to stall. However, under the action of RSI, stall can be induced in the adjacent flow channel, and then rotating stall is gradually formed. Rotating stall can be suppressed by various methods of reducing RSI. To a certain extent, the research makes up for the problem that conventional theory does not fully consider non-uniform and unsteady complex incoming flow when analyzing rotating stall. A connection between rotating stall and RSI is established, which can provide an important basis for further research on how to eliminate rotating stall.