Stall margin enhancement of a novel casing treatment subjected to circumferential pressure distortion

This paper presents the stall margin enhancement of a novel casing treatment subjected to circumferential pressure inlet distortion. Experimental results are carried out on a low-speed compressor. Experimental results show that the stall margin of the test compressor is gravely narrowed by circumferential pressure inlet distortion. The stabilization ability of this novel casing treatment and the pre-stall behavior of the compression system under the impacts of circumferential pressure distortion are shown in the present work. Although subjected to the inlet distortion, the stall margin can also be made up by 6%-8% due to the application of this novel casing treatment. Furthermore, the pre-stall dynamic results can indicate that the mechanism of this stabilization method is associated with two main observations, one is the weakening of the unsteady flow perturbations in the compressor, and the other is the delay in of the nonlinear amplification of the stall precursor waves.