COMPUTATIONAL ANALYSIS OF CENTRIFUGAL COMPRESSOR WITH GROOVES ON CASING

ABSTRACT Computational results of flow field in a centrifugal impeller with grooves on casing are presented in the paper. A low speed centrifugal compressor with 2% tip clearance is considered. Analysis is carried out for three different cases, one without grooves on the casing, second with two grooves on casing and third with three grooves on the casing. The three cases are studied at five different flow coefficients φ=0.28, 0.34, 0.42 (design value), 0.48 and 0.52 using Ansys-CFX. Pressure ratio improvement with two grooves on casing is observed. The leakage of flow over tip of the blade through the grooves from pressure side to suction side of the blade is interacting with passage wake near casing and reduction in passage wake region area is observed with two grooves on casing. Increase in the velocity of the fluid in passage wake is also observed with two grooves on casing. Increase in pressure ratio is observed for the casing with two grooves at all flow coefficients. For three grooves on casing also, increase of velocity in passage wake is observed but reduction in pressure ratio is observed due to more leakage flow. Reduction in pressure ratio for all flow coefficients is observed with three grooves on casing