非线性燃烧不稳定振荡幅值演化特征信号辨识方法研究

The pressure oscillation signal of nonlinear instability in solid rocket motor has obvious multi-order coexistence phenomenon,the amplitudes of different modes varies with time,and there is a process of oscillation energy transfer and evolution among the modes.In order to study the evolution mechanisms of energy transfer among nonlinear combustion instability modes,it is necessary to accurately decompose the oscillating signals first. In this paper,based on the variational mode decomposition(VMD)method,an adaptive mode decomposition method SPSO-VMD was proposed for nonlinear unstable oscillation signals of SRM,which solves the problem that the traditional VMD method cannot be adaptive,and greatly reduces the calculation time while improving the signal decomposition accuracy.Based on this method,the modes of a typical nonlinear combustion instability signal were decomposed and analyzed.The results show that this method can accurately obtain the frequency and amplitude of each mode in the nonlinear combustion unstable oscillation signal.The frequency errors are 0,and the amplitude errors are less than 0.5%.Finally,the proposed method is applied to a real motor oscillation data to obtain the amplitude information of each mode,which provides a key and accurate data support for the subsequent study of the energy transfer evolution among the modes.