The explosion thermal behavior of H2/CH4/air mixtures in a closed 20 L vessel

Abstract

In this work, the explosion thermal behavior of H2/CH4/air mixtures, at different equivalence ratios (0.6–1.6) and hydrogen volume fractions (0%–100), was investigated in a confined 20-L chamber. The parameters of explosion time and pressure, as well as the explosion heat loss were quantitatively studied and analyzed. Moreover, the dominant chain reactions of the explosion process and heat release were identified via the detailed mechanism of the Foundational Fuel Chemistry Model (FFCM1). The results indicated that an increased H2 volume fraction in the mixtures increased the peak explosion pressure, maximum pressure rise rate and deflagration index. In addition, the explosion duration and fast-burning period were greatly shortened. Both the adiabatic flame temperature and thermal diffusivity monotonically increased with increasing H2 volume ratio. Moreover, the enhancement effect of the H2 ratio on the thermal diffusivity of H2/CH4 mixtures was more prominent for fuel-rich mixtures than for fuel-lean mixtures. The obtained quantitative results are helpful for developing measures to prevent the potential explosion accidents.