Numerical and experimental study of the effects of the stagger angles of vane diffuser on the performance of centrifugal compressors

The performance maps of the centrifugal compressor under different diffuser stagger angles are measured, and the influence of different stagger angles of vanes on the stage performance as well as flow field is investigated. The study shows the performance map shifts when the diffuser stagger angle is altered; the influence of different stagger angles of vanes on the flowfiled inside centrifugal compressor is great, and large scale vortices appear on the diffuser vane under large incidence; an optimal diffuser stagger angle should exist at a fixed mass flow rate to make the diffuser have highest efficiency; the incidence corresponding to the highest efficiency is not zero at the design condition.