On Effects of Impeller-Diffuser Interaction in the "Radiver'' Centrifugal Compressor

In the present work, effects of impeller-diffuser interaction were investigated in the  “Radiver” centrifugal compressor stage exploiting CFD techniques. Two diffuser geometries, differing in the radial gap between impeller exit and diffuser inlet, were analyzed by means of both steady and unsteady computations at two different operating conditions. Physical mechanisms by which interaction affects the flow field were identified and discussed. Flow unsteadiness was found to marginally affect the stage performance, but to have a relevant impact on the flow field.