Abstract:

The inlet and exit fluctuating pressure signals of a compressor prior to "drift surge"are investigated by correlation and spectral analyses. It is found that the stochastic process of fluctuating pressure is no more stationary near the inception of the "drift surge". The surge of the tested engine under the, dynamic distortion is caused by rotating stall. The whole unsteady operating time for the engine to get into surging is about 5 seconds and the process is characterized by rotating stall cell spreading forwards from the rear stage over the whole annular passage of the compressor. It is worth notice that the tested engine is sensitive to pressure fluctuations with certain frequencies prior to the surge, but strict conclusion needs further experimental investigation.