Numerical Simulation of the Influence of Tip Clearance on Centrifugal Pump Impeller

The geometrical structure of centrifugal pump is very complicated,so the inner flow field is not only very complicated but also has strong 3-D and turbulence characteristics. Owing to the limitation of theory and experiment technology, at present the only way to gain the right and detailed inner flow-field of centrifugal pump is to use computer simulation method. In this paper,to reaserch the influence of tip clearance in flow field, two centrifugal impellers with tip clearance and without tip clearance are both investigated by computer simulation. Based on the result, the paper contrasts the characters of inner flow field in two impellers and captures the secondary flow in passage. It is concluded that with the clearance increase, the leakage flow makes the performance worse and strengthens the secondary flow. Accordingly, the computer simulation can remedy the deficiency of experiment and research the influence of leakage flow and offer advice for design and optimization of centrifugal pump impellers.