Bugler John, Somers Kieran P, Silke Emma J, Curran Henry J
Combustion Chemistry Centre, National University of Ireland, Galway, Ireland.
J Phys Chem A. 2015 Jul 16;119(28):7510-27. doi: 10.1021/acs.jpca.5b00837. Epub 2015 Apr 1.
This paper describes our developing understanding of low-temperature oxidation kinetics. We have investigated the ignition of the three pentane isomers in a rapid compression machine over a wide range of temperatures and pressures, including conditions of negative temperature coefficient behavior. The pentane isomers are small alkanes, yet have structures that are complex enough to allow for the application of their kinetic and thermochemical rules to larger molecules. Updates to the thermochemistry of the species important in the low-temperature oxidation of hydrocarbons have been made based on a thorough literature review. An evaluation of recent quantum-chemically derived rate coefficients from the literature pertinent to important low-temperature oxidation reaction classes has been performed, and new rate rules are recommended for these classes. Several reaction classes have also been included to determine their importance with regard to simulation results, and we have found that they should be included when developing future chemical kinetic mechanisms. A comparison of the model simulations with pressure-time histories from experiments in a rapid compression machine shows very good agreement for both ignition delay time and pressure rise for both the first- and second-stage ignition events. We show that revisions to both the thermochemistry and the kinetics are required in order to replicate experiments well. A broader validation of the models with ignition delay times from shock tubes and a rapid compression machine is presented in an accompanying paper. The results of this study enhance our understanding of the combustion of straight- and branched-chained alkanes.
本文描述了我们对低温氧化动力学不断发展的理解。我们在快速压缩机中研究了三种戊烷异构体在广泛的温度和压力范围内的着火情况，包括负温度系数行为条件。戊烷异构体是小分子烷烃，但其结构足够复杂，能够将其动力学和热化学规律应用于更大的分子。基于全面的文献综述，对烃类低温氧化中重要物种的热化学进行了更新。对近期从文献中获得的与重要低温氧化反应类别相关的量子化学推导速率系数进行了评估，并为这些类别推荐了新的速率规则。还纳入了几个反应类别以确定它们对模拟结果的重要性，并且我们发现，在开发未来的化学动力学机制时应将它们纳入。将模型模拟结果与快速压缩机实验中的压力-时间历程进行比较，结果表明，对于第一阶段和第二阶段着火事件的着火延迟时间和压力上升，两者都具有很好的一致性。我们表明，为了很好地复制实验结果，需要对热化学和动力学进行修正。随附论文中给出了使用激波管和快速压缩机的着火延迟时间对模型进行更广泛验证的结果。本研究结果加深了我们对直链和支链烷烃燃烧的理解。
