Abstract:
In this study, the differences in vibration acceleration data caused by different sampling frequency (10, 20, 50, 100, 200 kHz) of the large flow and high pressure combustion-heater were analyzed. And the cold blowing test, knock experiment and ignition test were carried out. Then, the root mean square (RMS), skewness, kurtosis in the time domain, the power spectral density (PSD) in the frequency domain, the wavelet transform in the time-frequency domain, and the polyreference least squares complex frequency (PolyLSCF) domain method for modal parameter identification were applied to analyze the vibration data at the sampling frequency of 10 kHz and 200 kHz. Finally, the mounting resonant frequency of the sensor, the natural frequency of the mounting base and the facility, as well as the main frequency band in which the heater operates, are obtained and deviate by < 5% from the result of the acoustic-structural coupling frequency formula.The results show that the vibration of heaters can be effectively characterized by using a sampling frequency of 10 kHz, and this method can provide a reference for the selection of sampling frequency for vibration testing of large and complex combustion facility.