Study on noise-vibration coupling characteristics of premixed methane-air flame propagation in a tube with an acoustic absorption material.

To study the influence of an acoustic absorbing material (AAM) on the noise and vibration of a methane-air deflagration flame in a square plexiglass tube, a high-speed video camera, pressure sensors, and a noise and vibration tester were used to test the deflagration flame propagation velocity, deflagration pressure, noise and wall vibration characteristics in the tube. The tube length is 540 mm with a cross section of 80 × 80 mm2, and its wall thickness is 12 mm. The experimental results indicate that under the conditions of 8.96% CH4 by volume and fixed repeating obstacles, the built-in AAM of polyester fiber cotton can reduce the peak velocity of the deflagration flame propagation by 11.3%. In addition, the average maximum sound pressure level of the deflagration flame noise is decreased by 17.6%, and the peak vertical vibration velocity of the tube outer wall is decreased by 85.6%. Therefore, using AAM can effectively attenuate the flame propagation and its harmful effects. For the case with an AAM, the flame propagation velocity and deflagration pressure reached the maximum values at 33 ms after ignition, and the values were 62.50 m s-1 and 27.74 kPa, respectively. Similarly, the time history curves of the noise and the tube wall vibration caused by deflagration presented certain correlations. The experimental results and analysis in this paper provide reference values for controlling the hazards of gas explosions in underground mines and other combustible gases in industrial pipelines.