Research On Propagation Of Gas Flame In Tube And Coupling Characteristics Of Noise And Vibration

In recent years, gas explosion accidents occur frequently. These accidents caused huge losses to the national economy. To prevent gas explosion accident, make contingency plans for unexpected incidents, disposal of gas explosion accidents in time and effectively, the situation is so urgent to study the coupling effect between deflagration flame propagation parameters and noise, vibration.This paper mainly compared parameters which caused by methane-air premixed gas deflagration reaction in the square plexiglass pipe. These parameters include flame velocity, pressure, vibration, noise. The main conclusions are as follows:(1) This paper discusses the coupling relationship between parameters of methane-air premixed gas deflagration flame and noise & vibration for first time. Their variation of parameter presence high degree of consistency When the flame propagation speed up, the wall pressure, noise and vibration amplitude is large; when the flame propagation speed decreases, the wall pressure decreases, the amplitude of the vibration noise is also reduced. And they all have three regions:the growth zone (approximately 10ms), violent reaction zone (approximately 15ms), weak zone (approximately 40ms).(2) Sound-absorbing cotton makes instantaneous noise peak reduced by 15-18dB, there was obvious effect of reducing noise, group of non-sound-absorbing cotton in the experiment was got significantly greater noise than the group with sound-absorbing cotton. Peak vibration velocity of no sound-absorbing cotton group is around 7 times as the speed of sound-absorbing cotton group. It shows that the effect of vibration reduction bring by absorbing cotton is obvious. The main vibration frequencies are 23.19Hz and 25.64Hz, little difference between the two, indicating that the vibration frequency of plexiglass pipe is approximately natural low-frequency.(3) Vibration of non-absorbing cotton group is instantaneous is the release of energy with high intensity, while energy release of sound-absorbing cotton group is slow and distributed, it can cushion the damping effect.(4) Hilbert energy spectrum of the original signal decreasing from top to bottom in the color scale. Before the explosion that occurs a high environmental noise come into noise sensor, After the high-frequency part of the environmental noise, the detonation noise is mainly distributed below 500Hz. Marginal spectrum analysis has also indicate premixed-methane flame frequency in plexiglass tube is low frequency.(6) According to HHT analysis of noise and vibration signal, either noise or vibration frequency of methane-premixed flame in the tube is low frequency. But the frequency band of noise is wider, and the vibration frequency as small as only about 30Hz, the amplitude of vibration which carries more energy is greater.This paper takes HHT method to analyze methane deflagration flame which is an innovative point and can deepen our understanding of the energy released in the propagation characteristics of flame noise and vibration.