Progress in the Development of a Combustion Kinetics Database for Liquid Fuels

摘要

We describe our progress in the development of chemical kinetics databases for liquid fuels. The intention is to create kinetics databases that can be used to simulate all aspects of combustion across a wide range of equivalence ratios. This paper will include some brief comments on existing databases, a summary of current work and a discussion of future directions. Liquid fuels are complex mixtures containing hundreds of compounds. There are however a limited number of classes. There is general agreement that surrogate mixtures, with a limited number of compounds, can reproduce much of the combustion behavior of real fuels. The largest component in liquid hydrocarbon fuels are the linear alkanes and we have concentrated our work on this type of compound. The discussion will cover work on the development of a database for the cracking of heptane to form the small olefins and dienes that can be used as inputs to PAH/soot models. Primary emphasis has been on the unimolecular reactions that break the larger organic radicals to smaller components used in soot models. Rate constants on the isomerization and breakdown of all alkyl radicals from C4 to C7 and 1-olefinyl radicals from C4 to C6 have been determined. Recent work has dealt with the chemically activated decomposition of alkyl radicals from H addition to the olefins. These are competitive with the products from hydrogen abstract and will favor olefin as opposed to diolefin yields. The discrepancy between low and high temperature results on isomerization of alkyl radical has been assigned to tunneling effects. Work on the elementary reactions for butylbenzene decomposition was completed. Problems and extensions of this work to more general situation will be discussed.