Progress toward a unified detailed kinetic model for the autoignition of alkanes from C4 to C10 between 600 and 1200 K

A unified model with a single set of kinetic parameters has been proposed for modeling the autoignition delay times of a wide range of alkanes using detailed kinetic mechanisms automatically generated by software EXGAS. The validations were based on recent data of the literature obtained in shock tubes and in rapid compression machines. The compounds studied were n-butane, n-pentane, iso-pentane, neo-pentane, 2-methylpentane, n-heptane, iso-octane, n-decane, and mixtures of n-heptane and iso-octane. Investigated conditions are the following: temperatures range from 600 to 1200 K, including the negative temperature coefficient (NTC) region, pressures range from 1 to 50 bar, and equivalence ratios range from 0.5 to 2. Tests were also performed for results obtained in a jet-stirred reactor and a sensitivity analysis was performed in the case of n-heptane. Simulations using generated mechanisms for the nine isomers of heptane were performed and showed that the variations of autoignition delay times follows globally well that of octane numbers at 650 K in a rapid compression machine at 4 bar. The influence of pressure (from 3 to 200 bar) was theoretically investigated.