Effect of exciting frequency of casing treatment on transonic compressor performances

Experiments were conducted to explore the effect of unsteady exciting frequency of casing treatment on transonic compressor performances. Unsteady exciting frequencies were changed by changing the slot number of casing treatment. Compressor performances under four different exciting frequencies were respectively measured. Experimental results indicate that the unsteady exciting frequency due to number of slots of casing treatment is one of the most important factors for compressor performances. Compressor performances can be overall enhanced through optimizing this unsteady exciting frequency. For the transonic compressor herein, peak efficiency, stall margin and maximum flow mass can be improved by 0.17%, 19.86% and 0.81% respectively at near design rotating speed and these increases can be maximally extended to 1.13%, 57.84% and 1.57% respectively at low rotating speed.