Effects of grooved number of grooved casing treatment on stall margin

Experimental and numerical investigations were conducted to study the effects of grooved number of circumferential grooved casing treatment on a compressor performance. Four kinds of grooved numbers of circumferential grooved casing treatment were tested in a subsonic rotor. Experimental results show all grooved numbers of groove casing treatment increase the stall margin of the compressor. The maximum grooved number has the best effect in increasing the stable operating range. The least grooved number has inferior effect in improving the stable operating range. The calculated overall performance lines showed good agreement with the experiments. The fundamental flow mechanism was obtained by detailed analyzing the flow at the blade tip, which reveals the effects of grooved width of circumferential grooved casing treatment on compressor performance.