Experimental investigation of novel casing treatment on stall margin enhancement under inlet distortion

Inlet pressure distortion is a common factor which induces rotating stall of an aero-engine fan/compressor. A novel casing treatment is used to enhance the stall margin of the fan/compressor. In the present work, experimental study is conducted on the effect of the novel casing treatment in the conditions of inlet pressure distortion. The flow-pressure ratio characteristic of a low-speed fan under inlet distortion and its efficiency characteristic with casing treatment are also investigated. The results show that the flow-pressure curve moves to the lower-right direction under inlet distortion. The more the distortion becomes, the more the curve moves. The novel casing treatment improves the stall margin (5%-8%) significantly in the condition of different distortion degrees. As for efficiency characteristic, below 20% distortion, the casing treatment does not incur recognizable efficiency loss of the fan, while above distortion, the efficiency loss is about 1%-2%.