Research on Mono-Fractal Characteristics of Dynamic Pressure at the Outlet of Centrifugal Compressor Based on EWT

In this paper, the outlet dynamic pressure of 800kw centrifugal compressor is taken as the research object, and the nonlinear characteristics of the system under different working conditions are analyzed by using empirical wavelet transform combined with mono-fractal. Firstly, the characteristics of the dynamic pressure signal when the system enters the surge state from the steady state through the transition process are analyzed, and the spectrum analysis of the dynamic pressure signal is carried out. Secondly, the modal components of the signal are extracted by empirical wavelet transform and the signal is reconstructed according to the correlation coefficient. Finally, the autocorrelation function of the reconstructed signal in different states and its Hurst parameters are studied. The research results show that when the system enters the surge state from the steady state, the spectrum of the dynamic pressure signal gradually concentrates to the low frequency band. And, the autocorrelation function and Hurst parameter of the reconstructed signal can effectively reflect the working state of the system.