Experimental investigation on initiation mechanism, overpressure, and flame propagation characteristics of methane-air mixtures explosion induced by hexogen in a closed pipeline

Gas explosion accidents under shock wave stimulation cause more severe hazards than electric spark ignition. To explore the initiation mechanism and explosion characteristics of methane induced by shock waves. A series of experimental investigations of methane-air mixtures initiated by hexogen (RDX) was performed based on a self-developed closed pipeline. The effects of incident shock wave intensity and methane concentration on the characteristics of methane explosion were studied. The results indicate that methane participating in the reaction can significantly increase the positive pressure duration compared with RDX explosion. With the increase of incident shock Mach number (Ma), methane deflagration pressure increases and counteracts the attenuation of RDX detonation pressure. When the ignition distance is 0 cm, the overpressure inside the pipeline is directly proportional to the methane concentration from 5 vol% to 13 vol%. When the concentration approaches the upper explosion limit, the flame velocity exceeds the theoretical detonation velocity, resulting in the unstable detonation of methane in the pipeline.