Review of Variable Geometry Techniques Applied to Enhance the Performance of Centrifugal Compressors

Most centrifugal compressors are required to operate over a broad range of flow rates and to provide a high pressure ratio with high efficiency. In order to meet these demands the application of variable geometry techniques is often considered and applied. The potential areas for the application of variable geometry procedures lie at inlet to and discharge from the impeller. This paper reviews the application of inducer preswirl, variable vaneless diffusers and variable vaned diffusers, and summarises some turbocharger compressor results obtained at the University of Bath.