Laminar flame speeds, non-premixed stagnation ignition, and reduced mechanisms in the oxidation of iso-octane

Experimental data on the laminar flame speeds of iso-octane/air mixtures at atmospheric and elevated pressures were acquired using the counterflow flame and the outwardly expanding flame, while the non-premixed ignition temperatures were determined for an iso-octane pool in the stagnation flow of a heated air jet at atmospheric and slightly reduced/elevated pressures. These experimental measurements were compared with calculations based on the mechanisms of Curran et al. and Chaos et al., with the former mechanism systematically and substantially reduced, using directed relation graph and computational singular perturbation, to facilitate the calculation. It was found that the Curran mechanism yielded substantially higher laminar flames speeds as compared to the present experimental results while results from the Chaos mechanism agree well with the present measurements. These trends are in agreement with previous results on the laminar flame speeds for n-heptane. Both mechanisms yield acceptable comparison with the observed non-premixed stagnation ignition temperature.