Chemical Kinetic Modeling of Alkane Ignition

Tim BarckholtzExxonMobil Research and EngineeringFairfax, VirginiaThis talk will summarize work on extending high temperature kinetic models to lower temperatures, for which the ignition process is significantly different than that at high temperatures. A single, unified model has been constructed for the combustion of all alkane isomers from CH4 through C5H12 as well as for n C6H14, n C7H16, and iso C8H18. A variety of techniques were used in the assembly of the model. Sophisticated ab initio calculations were employed for the prediction of the isomerization rates of peroxy radicals; abstraction rates were generated by using linear free-energy relationships; and many rates were derived empirically or semi-empirically. The complete, pressure-dependent model has over 700 chemical species and 11,000 reactions. The performance of the model is quite good with respect to the prediction of ignition delays in rapid compression machines and other experimental devices. Finally, a methodology for the drastic reduction of reacting species in this model will be summarized, in which the sub-model for n-heptane can be reduced from approximately 250 species to less than 40 for use in CFD codes.

Location: Stauffer Science Lecture Hall, SLH, Room 100

Audiences: Everyone Is Invited

Contact: April Mundy