Impact of grooved width of grooved casing on stall margin improvement

Experimental and numerical investigations are conducted to study the effect of the grooved width of a grooved casing on the performance of a compressor. Three grooved widths of a circumferential grooved casing are tested in a subsonic rotor. Experimental results show that all the three groove widths of the grooved casing treatment increase the stall margin of the compressor. The narrow groove has the best effect on increasing the stable operating range while the effect of the two wider grooves is less satisfactory. The calculated overall performance lines show good agreement with the results of the experiment. The fundamental flow mechanism is obtained by a detailed analysis of the flow field at the blade tip, which indicates how the groove width of circumferential-grooved casing treatment affects compressor performance.