Investigation on the circumferential grooves effects in a two-stage axial flow compressor

Abstract

Abstract The performances of a two-stage industrial axial-flow compressor were tested to investigate the effects of circumferential grooves. The corresponding numerical models with four-blade cascade were set up. The numerical and test results showed that the operation range of the compressor near stall point can be extended obviously by the circumferential grooves. The internal flow field of the compressor was analysed numerically in detail, especially the tip leakage flow. It was found that stall occurred originally in the first stage and the local flow rate of the tip leakage was approximately proportional to the corresponding blade load. In addition, the local flow rate of tip leakage tended to decrease gradually along the flow direction near stall point. The tendency indicated that there were the most part of the blade load in the front of the rotor. It was proposed that the circumferential grooves could be set up at a specific stage in the multistage axial flow compressor where stall might occur originally to extend the operation range with lower manufacturing cost. Meanwhile, several circumferential grooves in the front segment of the rotor would be enough to play the effect on the stability enhancement for the axial compressor.