Theoretical Evaluation of Flow through a Mixed flow Compressor Stage

Flow through mixed flow compressor stage was evaluated theoretically to understand internal flow behaviour. Various shroud configurations in terms of clearance has been considered to see the effect of clearance on compressor performance. The blade to blade relative flow variation from impeller inlet to outlet was evaluated through theoretical analysis. A 3D viscous commercial code Fluent was used to analyse the flow through the impeller channel. Computations have been carried out for different operating conditions of speed and mass flow rates covering a wide range from choke to surge. It is identified constant tip clearance gives better performance over variable tip clearance. The recirculation zone at inlet of the impeller near the tip gets vanished as the flow reaches impeller exit. The classical jet wake flow at impeller exit as seen in radial machines was absent for the mixed flow impeller.