The effect of compound boundary layer suction on the aerodynamic performance of a high-load diffusion compressor cascade with a large camber angle was experimentally investigated through ink-trace flow visualization and outlet flow field measurement.Experimental results show that suction on the endwall mainly influences the suction surface corner;suction on the suction surface not only shrinks the endwall corner region

but also delays the transition of the suction surface boundary layer

and improves the flow field around the midspan;the whole flowfield is improved in the case of compound boundary layer suction

and the performance is superior to each of the former two at high suction flow rates as the interaction between the boundary layer of endwall and suction surface is better controlled.