关键词: 液体火箭发动机, 脉动压力, 傅里叶变换, 小波变换

Abstract: According to the characteristics of fluctuating pressure data of liquid rocket engine test, fast Fourier transform(FFT) and wavelet transform are introduced in this paper. Through the fast Fourier transform(FFT)of the fluctuating pressure data and the related vibration data, the acoustic vibration type of the engine unstable combustion is effectively determined by the spectrum analysis results.Based on the wavelet transform singularity detection method, the abnormal fluctuating pressure data in the start-up and shutdown stages are analyzed.Combined with the frequency spectrum information of relevant vibration measurement points, the singular point position can be accurately located in the time domain, and the information in the frequency domain can be extracted to effectively judge the burning condition and acoustic vibration type of propellant.The analysis results show that the above methods can be widely used in the analysis of fluctuating pressure data of other type tests of engines and assemblies.

Key words: Liquid rocket engine, Fluctuating pressure, FFT, Wavelet transform