Table 5 shows the tip leakage flow rate. Tip leakage flow of the blade type A and B is reduced due to the tip clearance change. In case of blade type A, the tip leakage flow is decreased by 19.4% from 0.0531 kg s–1 to 0.0428 kg s–1. In case of blade type B, the tip leakage flow is decreased by 16.2% from 0.0537 kg s–1 to 0.045 kg s–1. These results show the tip clearance variation has a great influence on the tip leakage flow rate. Tip clearance reduction caused by impeller deformation helps to reduce the interaction between the tip leakage vortex and the secondary flow, which enhanced the aerodynamic performance. It however increases the failure risk of the impeller and decreases the compressor running reliability.