Skeletal Chemical Kinetic Mechanisms for Syngas, Methyl Butanoate, n-Heptane, and n-Decane

Abstract

Skeletal chemical kinetic mechanisms are presented for combustion analysis of a series of fuels of interest in combustion systems. These models are obtained from their respective detailed chemical kinetic models using the global species sensitivity method in a formulation referred to here as alternate species elimination (ASE), reflecting the alternate elimination of chemical species from a mechanism in order to assess the resulting effect on the prediction ability of the model. Ignition delay times are used as the target global combustion property for the assessment of the chemical influence of a species. Three ignition conditions of lean, stoichiometric, and rich fuel/air mixtures at a temperature and pressure of 1050 K and 15 atm, respectively, are used to generate data for the model reduction process. The skeletal mechanisms obtained from this ignition-based reduction are tested for their ability to predict premixed flame propagation and diffusion flame structure. It is found that, by imposing an appropriate threshold on the ranked normalized changes in ignition delay times, these skeletal models capture a broad range of combustion processes beyond the homogeneous ignition process used to deduce them. The skeletal mechanisms presented in this work include syngas (31 species), methyl butanoate (MB) (88 species), n-heptane (122 species), and n-decane (89 species). These skeletal models reflect a reduction of at least 60% in the number of chemical species with respect to the detailed model. They are recommended for use in further computational combustion analysis since they result in a reduction in computational costs, and are provided as Supporting Information to this article.