posted on 2021-04-08, 10:29authored byWenhao Yuan, Long Zhao, Jiuzhong Yang, Zhongyue Zhou, Yuyang Li, Fei Qi
This
work reports an experimental and kinetic modeling investigation
on laminar premixed flame of p-xylene at 0.04 atm
and equivalence ratios of 0.75, 1.0, and 1.79. Intermediates such
as the p-xylyl radical, p-xylylene,
and styrene, as well as polycyclic aromatic hydrocarbons (PAHs), were
detected by using synchrotron vacuum ultraviolet photoionization mass
spectrometry. Based on our previous aromatic kinetic model, a detailed
kinetic model of p-xylene combustion was developed,
and the model was validated against the present flame structure data.
Model analysis work was also performed in order to reveal the important
reactions in p-xylene decomposition and oxidation.
The H-abstraction reactions leading to the p-xylyl
radical are found to control the consumption of p-xylene in all the three flames. In the rich flame, p-xylyl mainly suffers the H-elimination and isomerization reactions,
which produce p-xylylene and the o-xylyl radical, respectively. The further decomposition reactions
of the o-xylyl radical contribute to the production
of styrene, which is another important C8 intermediate
observed in the rich flame. In the stoichiometric and lean flames, p-xylyl mainly suffers the oxidation reactions by O, which
give p-methylbenzaldehyde as major product. The growth
pathways of PAHs in the rich flame were also investigated in this
work. Indenyl, indene, naphthalene, and phenanthrene were observed
as the abundantly produced bicyclic and tricyclic PAHs due to the
existence of direct formation pathways from the decomposition of p-xylyl radical.