Numerial simulation of incipient rotating stall characteristics in a mixed-flow pump

Rotating stall is an unstable phenomenon, which has an important influence on the performance of a mixed-flow pump. In this paper, the internal flow characteristics and the energy performance of a mixed-flow pump in incepient stall condition are numerically simulated using three turbulence models, namely the standard k-ε, k-ω and SST k-ω. The numerical results are analyzed and compared with the experimental results from an energy performance test and Particle Image Velocimetry (PIV). The analysis of the results shows that the turbulence models have significant influence on predicting the stall characteristics. The hump zone calculated by the SST k-ω turbulence model is more obvious than that obtained by using the k-ε and k-ω models; however the flow rate condition at the lowest point of the hump zone has little difference in the results from various turbulence models. The simulations with SST k-ω model can better capture the stall vortex and separated flow in the mixed-flow pump compared to the other two models. Furthermore, the efficiency of the pump and stall flow field predicted by the SST k-ω model gives the best agreement with the experiment data.