It is recognized today that centrifugal compressors exhibit their inherent characteristics at lower flow rate and this is due to the reversed flow phenomena taking place within compressor channels. In the present study, the authors precisely observed these reversed flow phenomena within compressor channels in an experiment. Many sorts of measuring techniques were employed to clarify the nature of them. By these investigations, it became clear that these phenomena primarily depended on the shocked inlet condition at inducer inlet, where shocked inlet condition designated that the direction of the relative velocity at the inducer inlet deviated from the inducer mean camber line there. Especially, the balance of the body forces and the pressure gradients between the separated wake flow and the main flow was a predominant factor. Reversed flow phenomena observed within compressor channels appeared within the inlet duct near the shroud casing, within the inducer and impeller channel as a three-dimensionally skewed eddy, at the walls of the diffuser, and along the shroud casing.

This content is only available via PDF.