By analyzing 36 groups test data of four models axial compressors

it’s found statistically that the root mean square (RMS) of pulsation of compressors outlet total pressure is subject to normal distribution;the RMS and its standard deviation vary from different models and/or working speeds.An automatic threshold surge-detecting on-line system was designed based on statistical characteristics.Experiments demonstrate that alarm signals can be given at the time of surge.This method is simple in calculation

and has great value in engineering application.