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

Abstract

The present work reports experimental investigations on laminar burning velocity variation of CH4+H2+air mixtures at elevated temperatures (300–650 K) using an externally heated diverging-channel method. The effect of mixture equivalence ratio (ϕ = 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 ϕ = 1.1. Reaction pathway diagram interprets the major oxidation paths followed by reactants for higher carbon-consumption with varying H2 fraction. The P2 pathway involving ethane breakdown plays a major role in enhancing the burning velocity at rich mixture conditions.