Reduced chemical kinetic models of C1 - C4 alcohols using the alternate species elimination approach

This study presents four separate reduced chemical kinetic models of methanol/ethanol, propanol isomers, n- and iso-butanol, and n- and s-butanol isomers, derived from a comprehensive chemical kinetic model of C1-C5 alcohols using the Alternate Species Elimination approach. It is motivated by complexity of the detailed model (comprising 600 species and 4100 elementary reactions) and the need for simpler kinetic models for analysis of combustion of smaller alcohols. The reduced models are obtained on the basis of ignition delay time simulations with imposed thresholds on the resulting normalized changes in ignition delay times. The following reduced models are obtained: methanol/ethanol: 38 species and 197 reactions; propanol isomers: 68 species and 419 reactions; n- and iso-butanol: 140 species and 745 reactions; and n- and s-butanol: 134 species and 739 reactions. Predictions of ignition delay times by the reduced models are found to be in good with the detailed models. The reduced models are further tested against other relevant combustion properties. These properties include burning velocities of laminar premixed flames, global pyrolysis time scales, and heat release timing in Homogeneous Charge Compression Ignition engines. This verification shows that reduced models can replace the comprehensive model in combustion analysis without loss of predictive performance. The reduced models can also serve as starting models for developing combined chemical kinetic models of gasoline/diesel and alcohol blends.