Experimental Study of Surge Precursors in a High-Speed Multistage Compressor

Pressure measurements using high frequency response sensors have been carried out on the third rotor of the 3.5-stage high speed compressor CREATE (rotation speed: 11,543 RPM, Rotor 1 tip speed: 313 m/s) over the complete characteristic line and during the surge transient. Precursors to the instabilities occurring near surge are observable at stable operating points. Just before surge, these precursors characterized as rotating disturbances grow in amplitude and provoke the onset a stall cell after a variable duration, which finally triggers surge. This paper presents a detailed analysis of the phenomena of rotating instabilities and surge transient and shows that it is possible to develop an antisurge active control system based on the early detection of the precursors.