Reduced Chemical Kinetic Mechanisms for Hydrocarbon Fuels

Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, a variety of different reduced chemical kinetic mechanisms for ethylene and n-heptane have been generated. The reduced mechanisms have been compared to detailed chemistry calculations in simple homogeneous reactors and experiments. Reduced mechanisms for combustion of ethylene having as few as 10 species were found to give reasonable agreement with detailed chemistry over a range of stoichiometries and showed significant improvement over currently used global mechanisms. The performance of reduced mechanisms derived from a large detailed mechanism for n-heptane was compared to results from a reduced mechanism derived from a smaller semi-empirical mechanism. The semi-empirical mechanism was advantageous as a starting point for reduction for ignition delay but not for PSR calculations. Reduced mechanisms with as few as 12 species gave excellent results for n-heptane/air PSR calculations but 16-25 or more species are needed to simulate n-heptane ignition delay. Presented at the AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, held in Los Angeles, CA, on 20-24 Jun 1999. Prepared in cooperation with University of California, Berkeley, CA. Prepared in collaboration with Lawrence Livermore National Laboratory, Livermore, CA, and Air Force Research Laboratory (AFRL), Wright-Patterson AFB, OH. The original document contains color images.