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Modeling ignition of a heptane isomer: improved thermodynamics, reaction pathways, kinetics, and rate rule optimizations for 2-methylhexane
Mohamed, Samah Y.; Cai, Liming; Khaled, Fethi; Banyon, Colin; Wang, Zhandong; Al Rashidi, Mariam J.; Pitsch, Heinz; Curran, Henry J.; Farooq, Aamir; Sarathy, S. Mani
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. The research at NUIG leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007- 2013/under REA grant agreement n° 607214 2017-03-21
Keyword(s): Rapid compression machine; Low temperature oxidation; Shock tube measurements; Group additive values; Pressure rate rules; Hydrocarbon radicles; Rate constants; Combustion; Alkanes; Mixtures; Chemistry
Publication Date:
2016
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Contributor(s): |~|
Institution: NUI Galway
Publisher(s): American Chemical Society
File Format(s): application/pdf
First Indexed: 2017-03-22 10:49:39 Last Updated: 2019-09-20 06:33:59