Computer-aided design of gas-phase oxidation mechanisms—Application to the modeling of n-heptane and iso-octane oxidation

Abstract

This paper first describes a computer package that permits the automatic generation of detailed oxidation and combustion kinetic models in the case of paraffins and isoparaffins. The system, which provides kinetic models in a CHEMKIN II format, includes the following:u⊙ A reaction base for small free radicals and molecules having fewer than three carbon atoms.⊙ A generator of detailed and comprehensive primary mechanisms.⊙ A generator of lumped secondary reactions of the lumped primary products.⊙ Computerized thermochemical and kinetic databases that provide data by means of the thermochemical kinetics techniques, as well as by using quantitative structure-reactivity relationships. ⊙ A reaction base for small free radicals and molecules having fewer than three carbon atoms. ⊙ A generator of detailed and comprehensive primary mechanisms. ⊙ A generator of lumped secondary reactions of the lumped primary products. ⊙ Computerized thermochemical and kinetic databases that provide data by means of the thermochemical kinetics techniques, as well as by using quantitative structure-reactivity relationships. The system was then applied to the generation of kinetic models of the oxidation of n-heptane and isooctane. The predictions of the models were compared with experimental results obtained by means of perfectly stirred reactors both in the high temperature range (950–1150 K, 1 atm) and in the low temperature range (600–850 K, 10 atm), which includes the negative temperature coefficient area. The agreement between the computed and the experimental values is correct both for conversions and for the distribution of the products formed, considering that no fitting of any kinetic parameter was done.