Design of a transonic centrifugal compressor for High-speed turbomachinery

The paper presents a design of a small-scale centrifugal compressor to match the performance of up to 20% larger diameter compressor in order to meet the demands for a higher mass flow rate and wide operating range for turbocharging applications. This development considers the 44 mm diameter impeller design involving transonic blading and state-of-the-art blade features. In the course of design, the investigation on the inducer blade angle β1 s and blade inducer-to-outlet radius ratio has shown to have a dominant influence on the magnitude of inlet relative Mach number. Diffuser width and volute A/R ratio are also observed to be parameters affecting the overall performance of the compressor stage. Based on the diffuser parametric study, the most efficient diffuser width equal to 70% of the blade exducer width is observed.

The performance of the present compressor stage is analyzed with computational fluid dynamics simulations and experimental tests. The comparison of the predicted and measured results of the 44 mm compressor stage shows a good agreement for overall performance. Besides, the 44 mm compressor stage having the most efficient diffuser width and enlarged volute A/R ratio shows a good overlap of performance with approximately 20% larger diameter (52 mm) compressor stage performance. This development demonstrates that the impeller with state-of-the-art design features are likely to contribute to enhancement of the compressor performance.