Mechanism of Thermal Decomposition of Endothermic Hydrocarbon Fuel n-Octane
LIU Chao, QIU Shuyi, HUANG Hongmei, GUO Ping, HUO Erguang
Key Laboratory of Low-grade Energy Utilization Technology & System of Ministry of Education, School of Energy & Power Engineering, Chongqing University, Chongqing 400030
Abstract: The pyrolytic feature of n-octane was investigated by utilizing ReaxFF molecular dynamics (RMD) simulations under the condition of different temperatures and the result was compared with density functional theory (DFT) simulations. The result indicates that there are eight main pathways in the initial reaction path of n-octane, which are divided into C-C bond rupture and C-H bond rupture. C-C bond rupture is easier than C-H bond rupture and it is difficult to break the bonds at the end of the molecular. The effect of temperature on the pyrolytic product was discussed and the main products of the pyrolysis are H2, CH4, CH2=CH2, and CH3-CH3 molecule is also observed in the pyrolysis process. The formation of H2 has two mechanisms, the reaction of the free radical attacking and the reaction of the combination of the free radicals. The formation me-chanism of CH4 is same as that of H2. The formation mechanism of CH2=CH2 is β bond break reaction of macromolecular radical. Our work presents the mechanism of n-octane thermal decomposition from a molecule level and provides a reference for studying the thermal decomposition of endothermic hydrocarbon fuel.
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