Effect of hub inclination angle on internal and external characteristics of centrifugal pump impellers

Abstract

The flow characteristics at a centrifugal pump impeller are significantly affected by the hub inclination angle (HIA). The large eddy simulation turbulence model is employed to simulate the centrifugal pump impeller internal flow at two HIA values under design (1.0 Qd) and off-design (0.55 Qd) conditions. The reliability of the simulation results is verified by comparing the results at a 0° impeller HIA and experimental data. The results show that an increase in HIA has a positive effect on the head of the centrifugal pump impeller, which exhibited a 5% relative deviation between HIA values of 0° and 40°. Under design conditions, there is a good and similar impeller internal flow at the two HIA values. Under off-design conditions, the relative velocity of the 40° impeller HIA channel inlet is 11.7% higher than that of the 0° impeller HIA, which reduces the flow attack angle and effectively suppresses stall. Moreover, for the 0° impeller HIA, fluctuation caused by the stall cells on the blade suction surface is observed, whereas such a phenomenon is not observed for the 40° impeller HIA.