Experimental studies on the explosion indices in turbulent stoichiometric H2/CH4/air mixtures

Abstract Explosion characteristics of the stoichiometric hydrogen/methane/air mixtures with different hydrogen fractions (λ) and different turbulent intensities (u'rms) in a fan-jet-stirred spherical explosion vessel. From the experimental results, it could be clearly found that both the maximum explosion overpressure (pmax) and the maximum rise rate of overpressure rose with the increase of u'rms, but the major reasons to such rising were not totally the same. In turbulence, with the increase of λ, pmax declined but (dp/dt)max rose, and such behaviours were mainly attributed to the completion on the variations between propagation speed and adiabatic explosion pressure. The explosion duration (tc) was also measured, it rose with the increase of u'rms and/or λ for the enhancement on propagation albeit such enhancement was attributed to different mechanism for different influence factors. The variations of deflagration index (KG) indicated that the hazardous level of stoichiometric hydrogen/methane mixtures would become more hazardous in the presence of turbulence. Furthermore, the heat loss during the explosion also was calculated and analysed. The results reported in this article could provide more basic but important information to practical utilizations of hydrogen/methane blended fuels, especially on the safety protection strategies.