Characteristics of the combustion of hydrogen–methane–air mixture in a closed vessel

We experimentally determined the combustion characteristics of hydrogen-methane-air mixtures in a closed vessel. For hydrogen-air mixtures at certain pressures, a sign change of the normal burn velocity pressure exponent is characteristic for $S_u>$ 0.5 m/sec. With the addition of methane to the hydrogen-air mixture, a sign change of the pressure exponent from positive to negative can occur even when there is an absolute increase in the normal burn velocity.