Compressor pressure investigation of surge onset at steady and unsteady operations of an automotive turbocharger

The paper presents a novel analysis on compressor outlet pressure for steady and unsteady pulsating flow conditions. Surge onset is monitored and investigated at steady and unsteady pulsating flow conditions via a pressure sensor at the compressor outlet. Although, the frequency of oscillation could be identified within the 3-30Hz frequency range, a threshold on the Fast Fourier Transform magnitude could be inadequate to differentiate between stable and unstable compressor operations. For this reason, average values and coefficient of variation for the FFT magnitude in the 3-30Hz frequency range are investigated, identifying characteristics of surge onset under steady and pulsating flows.