Distribution of surge waves at inlet exit section for a aeroengine

The asymmetric distribution of total pressure distortion is produced by using disturbing inserted-board in the air inlet.When the aeroengine surges were appearing,at the inlet exit section,the surge pressure waves at two different rotating speeds were measured.The surge pressure signals were processed with wavelet analysis singularity theory with the module maximum value principle and Daubechies high-class multi-scale wavelet analysis.Their distributing characteristics were found.It shows that in case of two different rotor speeds,the surge waves distributions are similar at the same section.Their frequencies and values have direct ratios with the rotor speeds.The pressure pulses are positive in the section centre and negative at the circumference.The values of the surge waves in the area around the center vertical bisector are larger than those in the area around the diagonal diameters to its left and right.These distributing characteristics were analyzed and it shows that the surge waves are caused by the high pressure compressor.The surge waves are the strongest in the area where the steady total pressure distortion are the strongest and in the area where no distortion occurs.