Dynamic characteristics of methane explosion flame propagation in three types of pipe

Abstract

In process industries, the pipe connecting the various process units has complex structures. An experimental system was established to examine the flame propagation in premixed methane explosions given various methane concentrations. Three types of vented pipe, a horizontal pipe, a vertical pipe, and a T-shaped pipe, were investigated. When the methane concentration was 10 vol%, the flame propagation velocity was maximised, and the time to reach maximum flame propagation velocity (ta) was the shortest, vmax in the T-horizontal pipe was higher than that in the T-vertical pipe. The attenuation coefficient of the velocity for the vertical part was 1.16. When the methane concentration was closer to 10 vol%, the maximum flame temperature Tmax and maximum explosion pressure Pmax were higher, and the response time differences among thermocouples at different positions were more minor. The vertical bifurcation structure enabled shunting of the methane explosion shock wave and energy, and the attenuation on T and P reached up to 49.08% and 13.91%. The attenuation coefficients for the Tmax and Pmax in the vertical part were 1.50 and 1.08, respectively. The findings can provide theoretical basis for reducing and controlling the risk of pipeline accidents involving natural gas explosions.