In order to identify the number of stall cells during rotating stall process

a method was presented in this paper. Firstly

the phase and amplitude characteristics of pressure fluctuation during stall process were drew in the polar coordinate

and then the number of stall cells was obtained by judging the waveform displayed. After comparison with the traditional method

it shows that this method for determining the number of stall cell is better than original one thanks to its noise immunity and certain degree of precision. Besides

the method can also visualize the areas of stall in circumference and occurrence and development of stall inception in compressor.