Experimental investigation on the effects of unsteady excitation frequency of casing treatment on transonic compressor performance

The importance of the unsteady effects between casing treatment and rotor is still not clear. Experiments are conducted in a transonic compressor with arc skewed slot casing treatment configurations. The experimental results indicate that the unsteady excitation frequency due to slot number of casing treatment is one of the most important factors influencing compressor performance. And compressor performance can be overall enhanced through optimizing this unsteady excitation frequency. For the transonic compressor herein, peak efficiency, stall margin and the maximum flow mass can be improved by 0.17%, 19.86% and 0.81% respectively at near design rotating speed, which can reach up to 1.13%, 57.84% and 1.57% respectively at part design speed.