Abstract Reactions contributing to the generation of the explosive time scale that characterise autoignition of homogeneous stoichiometric CH4/air mixture are identified using two different chemical kinetics models; the well known GRI-3.0 mechanism (53/325 species/reactions with N-chemistry) and the AramcoMech mechanism from NUI Galway (113/710 species/reactions without N-chemistry; Combustion and Flame 162:315-330, 2015). Although the two mechanisms provide qualitatively similar results (regarding ignition delay and profiles of temperature, of mass fractions and of explosive time scale), the 113/710 mechanism was shown to reproduce the experimental data with higher accuracy than the 53/325 mechanism. The present analysis explores the origin of the improved accuracy provided by the more complex kinetics mechanism. It is shown that the reactions responsible for the generation of the explosive time scale differ significantly. This is reflected to differences in the length of the chemical and thermal runaways and in the set of the most influential species.

中文翻译：

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CH 4 /空气均质自燃：两种化学动力学机制的比较

摘要 使用两种不同的化学动力学模型确定了有助于产生表征均质化学计量 CH4/空气混合物自燃特征的爆炸时间尺度的反应；众所周知的 GRI-3.0 机制（53/325 个物种/与 N-化学反应）和来自 NUI Galway 的 AramcoMech 机制（113/710 个物种/无 N-化学反应；Combustion and Flame 162:315-330, 2015）。尽管这两种机制提供了定性相似的结果（关于点火延迟和温度曲线、质量分数和爆炸时间尺度），但 113/710 机制显示出比 53/325 机制更准确地再现实验数据。本分析探讨了由更复杂的动力学机制提供的精度提高的起源。结果表明，负责产生爆炸时间尺度的反应有显着差异。这反映在化学和热失控的长度以及最有影响力的物种集合上的差异。