Shock tube and modeling study of 2,7-dimethyloctane pyrolysis and oxidation
Type
ArticleKAUST Department
Chemical Engineering ProgramClean Combustion Research Center
Combustion and Pyrolysis Chemistry (CPC) Group
Physical Science and Engineering (PSE) Division
Date
2015-05Permanent link to this record
http://hdl.handle.net/10754/566165
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High molecular weight iso-paraffinic molecules are found in conventional petroleum, Fischer-Tropsch (FT), and other alternative hydrocarbon fuels, yet fundamental combustion studies on this class of compounds are lacking. In the present work, ignition delay time measurements in 2,7-dimethyloctane/air were carried out behind reflected shock waves using conventional and constrained reaction volume (CRV) methods. The ignition delay time measurements covered the temperature range 666-1216K, pressure range 12-27atm, and equivalence ratio of 0.5 and 1. The ignition delay time temperatures span the low-, intermediate- and high-temperature regimes for 2,7-dimethyloctane (2,7-DMO) oxidation. Clear evidence of negative temperature coefficient behavior was observed near 800K. Fuel time-history measurements were also carried out in pyrolysis experiments in mixtures of 2000ppm 2,7-DMO/argon at pressures near 16 and 35atm, and in the temperature range of 1126-1455K. Based on the fuel removal rates, the overall 2,7-DMO decomposition rate constant can be represented with k =4.47×105 exp(-23.4[kcal/mol]/RT) [1/s]. Ethylene time-history measurements in pyrolysis experiments at 16atm are also provided. The current shock tube dataset was simulated using a novel chemical kinetic model for 2,7-DMO. The reaction mechanism includes comprehensive low- and high-temperature reaction classes with rate constants assigned using established rules. Comparisons between the simulated and experimental data show simulations reproduce the qualitative trends across the entire range of conditions tested. However, the present kinetic modeling simulations cannot quantitatively reproduce a number of experimental data points, and these are analyzed herein.Citation
Li, S., Sarathy, S. M., Davidson, D. F., Hanson, R. K., & Westbrook, C. K. (2015). Shock tube and modeling study of 2,7-dimethyloctane pyrolysis and oxidation. Combustion and Flame, 162(5), 2296–2306. doi:10.1016/j.combustflame.2015.01.027Publisher
Elsevier BVJournal
Combustion and Flameae974a485f413a2113503eed53cd6c53
10.1016/j.combustflame.2015.01.027