Investigation on methane-air explosion overpressure in bifurcated tubes according to methane concentrations and bifurcation angles

Abstract

To understand the maximum overpressure propagation characteristics of methane-air explosion in a bifurcated tube, the distribution and mutation coefficient of maximum overpressure caused by methane-air explosions were investigated with various methane concentrations (5%, 7%, 9%, 11%, and 13%) and various bifurcation angles (30°, 45°, 60°, and 90°). The results show that: in terms of the overall trend, the increase in tube bifurcation angle is positively correlated with the maximum overpressure value of methane-air explosion in the main and branch tube sections, and the increase in these values was larger for the former. The methane concentration also significantly affects the explosion maximum overpressure in the main and branch tube sections. The closer the methane concentration is to the stoichiometric concentration, the greater the explosion maximum overpressure. The attenuation amplitude of the explosion maximum overpressure before and after the bifurcation point is affected by both the bifurcation angle and the methane concentration. The greater the bifurcation angle of the tube, the closer the methane concentration is to the stoichiometric concentration, the smaller the attenuation amplitude of the explosion overpressure in the main tube section before and after the bifurcation point, and the greater the attenuation amplitude of the explosion overpressure in the branch tube section before and after the bifurcation point. The research results can provide guidance for the design and implementation of explosion prevention and suppression measures in coal mines.