Experimental and modeling study on auto-ignition of methane/hydrogen blends at elevated pressures

Both experimental and simulated ignition delay times were obtained behind reflected shock waves for the diluted stoichiometric methane/hydrogen blends with hydrogen fractions of 20%, 60%, and 80%. Test temperatures are from 1000 K to 1820 K and pressures are from 0.5 to 2.0 MPa. Results showed that increase in hydrogen fraction can promotes significantly the ignition of methane due to higher activity of hydrogen. Pressure-dependence of auto-ignition was observed in three ignition regimes (methane chemistry dominating ignition, combined chemistry of methane and hydrogen dominating ignition and hydrogen chemistry dominating ignition). Kinetic model, NUIG Mech C5-49, was used and validated against current ignition data. It was found that NUIG Mech C5-49 can give a good prediction for all test mixtures. A fuel flux analysis was performed to explain the chemical interaction between methane and hydrogen.