Research On Analysis And Prediction Of Compressor Unstable Signal Based On Orthogonal Wavelet

With the constant improvement of maneuverability, thrust-weight ratio and efficiency for modern aircraft, aero-engine is easily into unstable working state. As a core component of high-performance gas turbine engine, compressor occurs to stall and surge caused by disturbance. It results in blade fracture, structural damage and over-temperature combustion chamber, even severe danger of air parking. To meet the working stability of the new generation aero-engine, it is necessary to carry out analysis and prediction of the unstable signal characteristics for compressor. The traditional research on the unstable characteristics for compressor was based on Fourier transform, but it couldn’t reflect the transient information of the unstable signal, so it has some limitations.This paper carries out the research analysis and prediction on compressor instability signal based on orthogonal multi-resolution wavelet. The main work of this thesis is as following:(1)In comparison of different orthogonal wavelet functions, this paper selected orthogonal multi-resolution method to analyze and predict the unstable signal of the compressor.(2)Normal working data and unstable data for dynamic pressure signal of the compressor was analyzed with multi-resolution Db wavelet, the signal wavelet coefficient was determined.(3)Time and frequency of rotating stall and surge for compressor was determined based on the mean and variance method among statistics. This paper researched the different threshold function to determine the critical threshold value.(4)The software of instability analysis based on orthogonal wavelet for compressor was developed and verified.The result shows that the research work could analyze and predict the unstable state for compressor efficiently.