Effect of Ignition Delay Time on Explosion Characteristics of Methane and Coal Dust Hybrid Mixtures

To study the effect of coal dust on methane explosion characteristics under different turbulent environments, based on 20 L explosion sphere, the mixed explosion experiments of 0 g/m³, 25 g/m³, 50 g/m³,100 g/m³, 200 g/m³ coal dust and 6.5%, 9.5%, 12% methane hybrid mixtures were obtained under the condition of ignition delay time 60 ms and 120 ms, respectively. The results show that the increase of the ignition delay time has a small effect on the maximum explosion pressure of methane explosion, and reduces the maximum pressure rise rate significantly. When coal dust is involved, the increase of the ignition delay time can reduce the maximum explosion pressure and the maximum pressure rise rate under the three methane concentrations. When the methane concentration is 9.5%, the optimal coal dust concentration is different under the two kinds of ignition delay time. The smaller the ignition delay time is, the smaller the optimal coal dust concentration is. The methane concentration is 12%, when the ignition delay time is 60 ms, the maximum explosion pressure and the maximum pressure rise rate are more sensitive to high concentration coal dust, when the ignition delay time is 120 ms, the maximum explosion pressure and the maximum pressure rise rate are more sensitive to low concentration coal dust.