title: Modeling Ignition of a Heptane Isomer: Improved Thermodynamics, Reaction Pathways, Kinetics, and Rate Rule Optimizations for 2-Methylhexane.
abstract: Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important to investigate the combustion behavior of real fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracies in certain portions of the models. This study focuses on updating thermodynamic data and the kinetic reaction mechanism for a gasoline surrogate component, 2-methylhexane, based on recently published thermodynamic group values and rate rules derived from quantum calculations and experiments. Alternative pathways for the isomerization of peroxy-alkylhydroperoxide (OOQOOH) radicals are also investigated. The effects of these updates are compared against new high-pressure shock tube and rapid compression machine ignition delay measurements. It is shown that rate constant modifications are required to improve agreement between kinetic modeling simulations and experimental data. We further demonstrate the ability to optimize the kinetic model using both manual and automated techniques for rate parameter tunings to improve agreement with the measured ignition delay time data. Finally, additional low temperature chain branching reaction pathways are shown to improve the model's performance. The present approach to model development provides better performance across extended operating conditions while also strengthening the fundamental basis of the model.
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Samah Y
authors.initials: SY
authors.lastname: Mohamed
authors.affiliation: Institute for Combustion Technology, RWTH Aachen University , 52062 Aachen, Germany.
authors.forename: Liming
authors.initials: L
authors.lastname: Cai
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Fethi
authors.initials: F
authors.lastname: Khaled
authors.affiliation: Combustion Chemistry Centre, Ryan Institute, School of Chemistry, National University of Ireland , Galway, Ireland.
authors.forename: Colin
authors.initials: C
authors.lastname: Banyon
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Zhandong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Mariam J
authors.initials: MJ
authors.lastname: Al Rashidi
authors.affiliation: Institute for Combustion Technology, RWTH Aachen University , 52062 Aachen, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Pitsch
authors.affiliation: Combustion Chemistry Centre, Ryan Institute, School of Chemistry, National University of Ireland , Galway, Ireland.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Curran
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Aamir
authors.initials: A
authors.lastname: Farooq
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal, 23955-6900, Saudi Arabia.
authors.forename: S Mani
authors.initials: SM
authors.lastname: Sarathy