Effect of tip injection on the performance and the flow of near-stall condition of transonic axial compressor rotor was investigated numerically.The result shows that the stall margin of this transonic rotor gains an absolute improvement of 4.48% by tip injection while the efficiency remains unchanged at the injection angle of +65?.Furthermore

the separation on the suction side of the rotor and intensity of the tip leakage vortex are both weakened.Besides

the trajectory of the tip leakage is more inclined to the suction side of the blade which mainly leads to the increase of stall margin.