Impeller loss reduction in multi-stage centrifugal compressors

Abstract

Loss generation features for the first stage impeller in a multistage centrifugal compressor are examined using three-dimensional RANS computations. The calculations were carried out for a baseline configuration and for seven other impeller configurations, with the constraints of constant mass flow and constant work per unit mass flow. The computations showed an 8 percent reduction in loss, compared to the baseline, for a configuration that incorporated 60% of the total casing blade angle change in the front 20% chord. Twodimensional interactive boundary layer computations were carried out to demonstrate links between the loss variation and the changes in boundary layer behavior in the front 20% of the blade passage.