The Krain impeller with total pressure ratio of 4.1 was taken as the research object. The effects of mass flow rate

rotational speed and tip clearance on the tip leakage vortex (TLV) trajectoryand the interface between the tip leakage flow and the main flow (ITLMF) were numerically investigated. Results showed that the decrease of mass flow rate

the increase of the rotational speed and the decrease of the tip clearance made the TLV trajectory move away from the suction surface and the ITLMF move upstream. By simplifying the main flow and tip leakage flow interaction as the free-stream and counter-flow wall jet interaction

a subsonic centrifugal impeller stall-onset prediction model was developed. In this model

the momentum balance analysis was applied to identify the position of main flow/tip leakage flow interface. The tip leakage flow velocity was modeled. Zhao’s model was used to predict the TLV trajectory. The relationship between the virtual origin of tip clearance jet and the tip clearance was determined. Results showed that the stall point predicted by current model agreed well with CFD

with the root mean square error was below 2.42%.