Flow Studies in a Centrifugal Compressor Stage

The overall efficiency of a compressor is dependent on the design of both the impeller and the diffuser. The vaned diffuser reduces the operating range compared to the vaneless diffuser. However, by proper setting of the diffuser with reference to the impeller, it is possible to achieve a good stage performance. This paper describes the experimental investigation of the detailed flow behavior inside a centrifugal compressor stage for three different setting angles of the vaned diffuser with reference to the fixed impeller blade outlet angle. It is seen that diffuser setting angles lower than the impeller outlet flow angle gives wide operating range.