Experimental and numerical simulation study of the influence of CF3CHFCF3 on characteristic of hydrogen/methane/air explosion

The effect of CF3CHFCF3 on the explosion of hydrogen/methane/air mixtures at low hydrogen doping ratios (XH2 =10%) has been investigated on a closed visualisation experimental platform. Different equivalence ratios (? = 0.8, 1, and 1.2) and CF3CHFCF3 concentrations (XCF3CHFCF3 = 0%-5%) were considered. The results showed that the suppression effect of CF3CHFCF3 on the mixture was good under the conditions of different equivalence ratios. After the addition of CF3CHFCF3, both of the maximum explosion pressure and the maximum pressure rise rate decrease, which shows CF3CHFCF3 has an inhibitory effect on the explosion. However, pressure peak occurs earlier indicates that CF3CHFCF3 accelerated the progression of the explosion and facilitates its occurrence. The simulation results indicate that CF3CHFCF3 changes the mole fractions of the major species and increases the consumption of the O, H, and OH radicals. Besides, the results of sensitivity analyses show that CF3CHFCF3 not only play an inhibitory role but also enhances the laminar flame speed of the explosion flame. Meanwhile, the effect of CF3CHFCF3 on the reaction H + CH3 (+M) <=> CH4 (+M) is different under different equivalence ratios. This study can provide theoretical support for the safe use of hydrogen/methane/air mixtures.