Effects of Variable Inlet Guide Vanes on Small Centrifugal Compressor Performance

Abstract

Variable inlet guide vanes (VIGVs) have been developed for a small centrifugal compressor of automobile turbocharger. The effects of pre-whirl flow generated by VIGVs on compressor performance have been studied experimentally. Furthermore, the flow condition in impeller passage of the compressor with VIGVs has been compared to that of the compressor without VIGVs by using three-dimensional flow analysis. The results of experimental study have shown that pre-whirl flow is advantageous to the efficiency and surge characteristics of compressor. A weak fluid oscillation, which usually occurs in the region of high pressure-ratio and high mass flow rates, has been controlled by using VIGVs. The results of calculation of the viscous compressible flow have shown that the pre-whirl generated by VIGVs is effective in decreasing the area of the reverse flow which occurs at shroud suction side and smoothing the flow distribution between shroud and hub at the impeller exit.