Explosion and vented explosion behaviors of low-concentration gas in large-scale pipes

Abstract

The extraction, transmission, and use of low-concentration gas in coal mines are often challenged by potential accidents due to proximity to the combustion and explosion concentration limit. Water sealing of fire barriers and explosion venting devices guarantee the safe transmission of low-concentration gas. The propagation and venting of gas explosion under different concentrations are experimentally investigated in a DN500 mm pipe explosion propagation test system. The water sealing of fire barrier vented explosion field evolution of methane-air mixture at the stoichiometric concentration (9.5 vol%) is examined through Fluent numerical simulation to reveal the water sealing of fire barrier further vented explosion pattern of gas transmission pipelines under low concentrations. The explosion overpressure and flame propagation of low-concentration gas in pipes are observed and correlated. Based on their coupling relationship, the design basis for the installation location of the explosion venting device is derived. The vented explosion characteristics of low-concentration gas during pipe transmission are summarized, proving that this explosion venting technique enhances both the explosion venting device and explosion parameters. Our observations and analysis can offer useful clues to underground gas explosion and prevention in coal mines.