Numerical study on the propagation of CH4/H2 flame in a pipeline under different H2 enrichment conditions

Abstract

The flame characteristics of CH4/H2/air mixture were simulated and studied by continuously increasing the amount of hydrogen in a fixed volume pipeline segment. The parameters and intermediate product changes of different flame stages were given. Under the condition of lean oxygen, the competition between hydrogen and methane for OH radicals weakened the reaction process of CO+OH=CO2+H, resulting in the residual of unreacted intermediate products CO in the flame after region. The extremely fast reaction rate in the later stage of flame development causes CO concentration to quickly decrease below the equilibrium value. The phenomenon of adiabatic flame temperature occurs in the later stage of the flame. The concentration peak values of H and OH radicals have significant differences at different stages under the same hydrogen concentration conditions. This study found the influence characteristics of different hydrogen addition amounts and fuel concentrations on explosion stages in a limited volume.