Influence of Step Casings on the Cavitation Characteristics of Inducers

Abstract

Rotating cavitation (RC) in inducers mainly degrades performance with unstable radial force. In this paper, the influence of step casings on cavitation performance and the instabilities of inducers were numerically investigated. Firstly, a numerical scheme was validated by means of a comparison with experimental measurements taken for an original inducer (Model O). We then performed simulations with five different step casing models (Models A–E), in which the starting locations and enlargement sizes of the step casings were altered. The interaction between tip leakage flow and main flow in the inter-blade passages was found to highly affected by cavity structure and blade loading. Considering both cavitation performance and radial force, our results suggest that Model E is an alternative improvement. In short, this study provides a standard workflow for the effective suppression of rotating cavitation in inducers by the simple adoption of the step casing configuration presented here in engineering practice.