Experimental and numerical determination of laminar flame speeds of methane/(Ar, N2, CO2)-air mixtures as function of stoichiometry, pressure, and flame temperature

Abstract

By using the counterflow method, the laminar flame speeds of methane/(Ar, N 2 , CO 2 )-air mixtures have been accurately and extensively determined over the stoichiometric range from very lean to very rich, the pressure range from 0.25 to 2 atm, and flame temperature range from 1,550 to 2,250 K; independent variation in the flame temperature is achieved by substituting nitrogen in the air by an equal amount of argon or carbon dioxide. These data are expected to be useful for the partial validation of proposed kinetic mechanisms. In the present study numerical simulation of the experimental flame speeds has been conducted by using a C 1 mechanism and a full C 2 mechanism. The calculated results agree well with the experimental data, for both the C 1 and C 2 mechanisms, except for very rich mixtures for which there is substantial overprediction by the C 2 mechanism. Sensitivity analyses have also been performed where appropriate for enhanced insight into the controlling elementary reactions.