Experimental investigation on the effect of obstacle position on the explosion behaviors of the non-uniform methane/air mixture

Abstract

Gas explosions in the underground coal mines where the obstacles exist can cause significant damage. A current knowledge gap in methane safety research concerns the effect of obstacle position on the explosion process of non-uniform mixtures. In this work, the effect of obstacle position on the explosion behavior of non-uniform methane/air mixture is investigated experimentally. The results show that the triple flame structure appears during the combustion of the non-uniform mixture, which appears delayed with increasing obstacle position. Then, broken flocculent turbulent flames occur when the obstacle is set at 400 and 600 mm, with the strongest turbulent disturbance response at 400 mm case. Moreover, the results show that the maximum flame front velocities and the maximum values of overpressures are obtained at the obstacle position of 400 mm in both diffusion times. Additionally, two obvious pressure peaks are found, which appear at increasing intervals as the distance between the obstacle and the ignition source increases. Meanwhile, the maximum overpressure values ranks as Pmax(400 mm) > Pmax(200 mm) > Pmax(600 mm). The study of gas explosion flame characteristics that meet the actual working conditions of coal mines plays an important role in the prevention of explosion accidents.