Experimental study on the explosion characteristics of methane-air mixtures initiated by RDX in a rectangular venting chamber

Abstract

Methane-air mixtures initiated by Hexogen (RDX) were experimentally investigated in a custom-designed rectangular venting device. By changing the methane concentration, the overpressure characteristics and flame propagation were studied under the conditions of RDX detonation and electric spark ignition, respectively. The results indicate that, compared with spark ignition, the RDX explosion shock wave leads to the structural vibration and interacts with the flame, shortening the methane reaction time and substantially increasing the explosion overpressure. When the methane concentration is close to the equivalence ratio of unity, only one pressure peak occurs after the vent plate opening. The pressure peak caused by the interaction between acoustic waves and flames, P3, appears only at methane concentrations of 8 vol% and 13 vol% under RDX detonation. The acoustic vibration of the structure induced by different masses of RDX has a nonlinear impact on the increase of P3. The long reaction duration and the weakening of the shock wave result in a relatively small frequency of high-frequency oscillations at high concentrations.