The effect of initial pressure on explosions of hydrogen-enriched methane/air mixtures

Hydrogen-enrichment has been proposed as a useful method to overcome drawbacks (local flame extinction, combustion instabilities, lower power output, etc.) associated to turbulent premixed combustion of natural gas in both stationary and mobile systems. For the safe use of hydrogen-enriched hydrocarbon fuels, explosion data are needed. In this work, experimental tests were performed to evaluate the explosion parameters for stoichiometric hydrogen-methane blends in air, with the hydrogen molar content in the fuel varying from 30% up to 70%, at different initial pressures (1, 3 and 6 bar). Results allow quantifying the combined effects of hydrogen presence and initial pressure on maximum pressure, maximum rate of pressure rise and burning velocity.