In order to further explore the effect mechanisms of suction-side winglet under different tip clearance sizes

an experimental investigation on the variable tip clearance characteristics of the compressor cascade with/without suction-side winglet was carried out. Results showed that at 1% relative tip clearance size

the tip leakage flow suppressed three-dimensional separation on the corner of suction surface and endwall

the cascade loss and endwall blockage were both minimum; and this clearance size was found to be optimum tip clearance. The suction-side winglet reduced the strength of tip leakage vortex but resulted in a stronger passage vortex

and the three-dimensional separation zone was formed again. For the particular tip clearance

the loss and endwall blockage of cascade with winglet were both higher than the baseline tip cascade. In case of 2% and 3% relative tip clearance sizes

for the cascade with suction-side winglet

the tip separation became stronger

and the strength of tip leakage vortex was reduced. In case of these two tip clearance sizes

the total pressure loss coefficients of the cascade was reduced by 8.9% and 12.5%

respectively by the suction-side winglet

and the blockage coefficients with winglet were 6.9% and 6.3% lower compared with the cascade without winglet. For these three tip clearance sizes

the compressor cascade performance sensitivity to tip clearance variation was improved by the suction-side winglet

and the degree of outlet flow angle's underturning and overturning induced by leakage vortex was reduced by the suction-side winglet.