Research on the Time-Histories of Exited Radicals during the Combustion of Methylcyclohexane by Emission Spectroscopy
LI You-liang1, HE Jiu-ning1, ZHANG Chang-hua1*, LI Ping1, LI Xiang-yuan2
1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China 2. College of Chemical Engineering, Sichuan University, Chengdu 610065, China
Abstract：By using three monochromator!detecting systems, the light emissions of excited-state OH*, CH* and C*2 radicals during the transient combustion of methylcyclohexane at high temperatures behind the reflected shock wave have been measured. The dependence of the time-history and the relative intensity of excited radicals on the temperature have been obtained. The reflected shock temperatures are 1 200～1 700 K, the shock pressure is 1.5 atm, the mole fraction of methylcyclohexane is 0.1% and the equivalence ratio is 1.0. At the beginning of the combustion process, these three radicals were produced at the same time. The durations of these radicals became shorter when the temperature increases. At the same ignition temperature, the durations of CH* and OH* are longer than that of C*2. The C*2 signal disappears below 1 400 K. The emission intensities of OH* and CH* are not sensitive to the temperature at T<1 400 K. However, at high temperature (T>1 400 K), the peak intensity of CH* increases rapidly as temperature increases, while C*2 and OH* increase slowly. Current results were compared to the simulation results of corresponding chemical reaction mechanism. The obtained time-history of OH* radical matches well with the prediction of mechanism at low temperatures, but shows difference at high temperatures. The time-history of CH* radical matches well between experimental and simulated results at high temperatures, however, the simulated durations of CH* are longer than the experimental results at low temperatures. Current work provides experimental data to validate and optimize corresponding chemical reaction mechanism containing excited-state species.
李有亮1，何九宁1，张昌华1*，李 萍1，李象远2 . 发射光谱法研究甲基环己烷燃烧时激发态自由基时间历程 [J]. 光谱学与光谱分析, 2016, 36(01): 11-14.
LI You-liang1, HE Jiu-ning1, ZHANG Chang-hua1*, LI Ping1, LI Xiang-yuan2 . Research on the Time-Histories of Exited Radicals during the Combustion of Methylcyclohexane by Emission Spectroscopy . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(01): 11-14.
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