Stall behaviour of centrifugal compressor impeller for automotive turbocharger under pulsating flow conditions

Abstract

Centrifugal compressors for automotive turbochargers are operated under conditions with unsteady cyclic pressure pulsations caused by intake and exhaust of the engine. Because of its complexed unsteadiness, it is not fully revealed how internal flow fluctuates under such conditions, especially in stall or surge condition.

In this paper, the time variation of the internal flow angle was quantified by unsteady analysis which utilized a measured pressure pulsation of as a boundary condition. As a result, it was found that the 0 ~ 60% span at the leading edge of the impeller shows little time variation, but that remarkable unsteadiness appeared at 60 ~ 100% span, and it leads the tip stall.