On Performance Characteristics of a Centrifugal Compressor with Supersonic Impeller Tip Speed

Abstract

It is very important to examine whether the performance characteristics of a centrifugal compressor should fall rapidly as soon as the absolute velocity of the air at the impeller exit exceeds the local sonic velocity. The experiments were performed by the present author with a centrifugal supercharger coupled with an electric dynamometer of 300 HP. The conclusions of these experimental study were that (1) the performance characteristics showed no rapid breakdown when the absolute velocity of the air at the impeller exit exceeds the local sonic velocity, this velocity being 400 m/s or so on account of the temperature rise of the air in the impeller channel, and (2) the maximum obtainable value of the pressure ratio of single stage centrifugal compressor was found to be 2.79 at the tip speed of the impeller of 435.3 m/s in this case.