Experimental Study of the Laminar Flame Speeds of the CH4/H2/CO/CO2/N2 Mixture and Kinetic Simulation in Oxygen-Enriched Air Condition

Abstract The experimental study on the laminar flame speeds of the CH4/H2/CO/CO2/N2 mixture was carried out in oxygen-enriched air condition. The laminar flame propagation velocities of the blended gas were measured in a range of equivalence ratios (from 0.6 to 1.4) and oxygen concentrations (from 21 to 33%) using a Bunsen flame. Comparisons between the experiments and calculations show that the GRI Mech 3.0 mechanism can well predict the laminar flame speed of the blended gas in oxygen-enriched conditions. The laminar flame propagation velocities were enhanced by the increasing oxygen concentration, while the reaction pathway of fuel changed little. The effects of each species of the CH4/H2/CO/CO2/N2 mixture on the laminar flame speeds were discussed. Results show that the laminar flame speed is promoted by the increase of H2 and CO, while the laminar flame speed is decreased by the increasing CH4, CO2, and N2 concentrations. The inhibition effect of CO2 on the laminar flame speed is bigger than that of N2, which is due to the difference in the properties of CO2 and N2.