A numerical study on the effects of hydrogen addition levels, wall thermal conductivity and inlet velocity on methane/air pre-mixed flame in a micro reactor

Abstract

<em>In this study, the effect of the levels of hydrogen addition to methane-air premixed flame in a micro-stepped reactor has been studied numerically. In addition, the effects of mixture velocity and walls' thermal conductivity (K_w) on the flame's location, temperature, and species distribution in a micro reactor were calculated using a 2D numerical laminar steady code. The results showed that an increasing level of hydrogen in the methane-air mixture probably improves the combustion process in a micro reactor by intensifying the flame speed, adiabatic flame temperature and the generation of some crucial species (such as OH, H, HCO, HO₂, and H₂O₂). Further, it was found that the addition of hydrogen to methane can shift the flame towards the inlet. In this way, it probably guarantees the flame's presence in certain conditions compared to cases of no hydrogen addition. In conclusion, it is shown that the temperature distribution along the axis and the wall of the micro reactor can be dependent on the amounts of hydrogen added to the methane-air mixture.</em>