Analysis of Francis Pump-Turbine Runner Cavitation Flows in Pump Mode

摘要

Pump-turbine works in pump and turbine modes, and its hydraulic performance in pump mode is more important than that in turbine mode. The cavitation is an important factor influencing hydraulic performance in pump, especially when designing the runner. The paper studies pump cavitation flow of model pump-turbine runner and its cavitation performance. That can be a method to help design and chose pump-turbine runner. The hydraulic performance and cavitation is analyzed in different net positive suction head (NPSH) and discharge. The result shows that NPSH simulated by cavitation flow is better than that simulated by no cavitation flow. The simulation result also shows that cavitation places near the band of pump blade inlet on suction side when the pump discharge is small, and cavitation sites near the band of pump blade inlet on pressure side when the discharge is large. The hydraulic performance of pump runner will not change until watervapor accounts for about 42 percent of total volume.