Computational Analysis of Scroll Tongue Shapes to Compressor Performance by Using Different Turbulence Models

Abstract

A scroll is used to collect and transport swirling fluid produced by impeller and diffuser. Scroll or volute is one of the key components of centrifugal compressors. Design of the scroll not only impacts compressor efficiency but also influences operating range of the compressor. In this study, Navier-Stokes equations with both the zero-equation turbulence model and the k-ϵ turbulence model were used to simulate flows inside a single stage compressor. Detailed flow simulations for a large cut back tongue scroll are presented and discussed. Studies showed that a large cut back rounded tongue scroll provided good operating range without dropping compressor peak efficiency dramatically. The turbulence model influences to the calculation were discussed and some suggestions for scroll flow modeling are made. The numerical results obtained using two turbulence models were compared and showed agreement reasonably well with experiments in overall compressor performance. Although the k-ϵ model behaves well inside the boundary layer, it was not decisively better than the Zero-equation model for compressor stage performance predictions.