Paper 21: Investigation of Flow in the Nozzle-Less Spiral Casing of a Radial Inward-Flow Gas Turbine

Abstract

Nozzle-less spiral casings are used frequently with radial inward-flow gas turbines of small turbochargers for automotive type diesel engines. The broad performance characteristics and low cost of this type of casing are two particularly attractive features for turbocharger applications. Considerable data on the performance of radial inward-flow gas turbines have appeared recently in the technical literature, but in contrast very little has been published on the performance of volute casings. The paper presents the results of a theoretical and experimental investigation in which three nozzle-less volute casings of a 2·85-in diameter turbine were studied. The theoretical analysis, based on the assumptions of steady isentropic one-dimensional flow and the conservation of mass and of angular momentum, is essentially design orientated.