The tip leakage flow directly affects the performance of the centrifugal compressor. The influence of the independent change of the radial and axial tip gaps and the influence of the distribution of the tip gap on the centrifugal compressor internal flow field and performance were studied by numerical simulation. The influence law of different height and shape of the centrifugal compressor tip gap on its performance was summarized. Result showed that increasing the centrifugal compressor gap would reduce the efficiency at near surge condition and design condition; increasing the radial gap solely

from 01 mm to 04 mm

could broaden the choke mass flow range by 388% and improve the performance of the centrifugal compressor near blockage condition; increasing the axial gap solely had no effect on the performance at near choke condition. The shrinking distribution of tip gap increased the efficiency of the centrifugal compressor by 023%.