Tip Clearance Effects on Performance of a Centrifugal Compressor

Abstract

Abstract-Tip clearance effects on flow field of a low speed centrifugal compressor performance is tested experimentally by using partial shroud (PS) attached to the rotor blade tip at three values of tip clearances i.e. = 2.2%, 5.1 % and 7.9 % of blade height at trailing edge are examined at three flow coefficients 0.18, 0.28, and 0.34. The effect of tip clearance on total pressure coefficient and static pressure coefficient exit of the compressor is analyzed. The drop in static pressure coefficient and total pressure coefficient with increase in tip clearance is found to be high at the tip of the blade due to high pressure fluid leakage at the tip of the blade. Performance reduction with tip clearance is observed. The mass averaged total and static pressures at the rotor exit at the three values of tip clearances clearly show that partial shrouds are beneficial in improving the pressure rise of the compressor. This benefit is found to be more at the higher value of tip clearance tested