Experimental investigations on laminar burning velocity variation of CH4+H2+air mixtures at elevated temperatures

The present work reports experimental investigations on laminar burning velocity variation of CH4+H-2+air mixtures at elevated temperatures (300-650 K) using an externally heated diverging-channel method. The effect of mixture equivalence ratio (phi = 0.7-1.3) and H2 fraction (0-50% by volume) on burning velocity have been reported at elevated temperatures. The experimental measurements are compared with numerical simulations using GRI Mech 3.0 and FFCM-1 kinetic models. The obtained results exhibit an increase in the laminar burning velocity with H2 fraction due to the formation of H-atom as an intermediate. The temperature dependency is established through a power-law correlation. The temperature-exponent shows a parabolic variation with a minimum value at phi = 1.1. Reaction pathway diagram interprets the major oxidation paths followed by reactants for higher carbon-consumption with varying H-2 fraction. The P2 pathway involving ethane breakdown plays a major role in enhancing the burning velocity at rich mixture conditions. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.