Abstract The reliable chemical mechanisms with compact scale play an important role in engine modeling. In this research, a new method was presented to reduce the large-scale reaction kinetic mechanisms through the global sensitivity analysis on the reaction classes/sub-mechanisms in detailed mechanisms. In the present method, the importance of each reaction sub-mechanism in a detailed mechanism was first assessed using the Morris method. Then, the crucial reaction classes in the fuel-specific sub-mechanism were identified based on their significance on the detailed mechanism predictions and their coupling relationship using the Morris method and the path sensitivity analysis. Third, the reactions in the unimportant sub-mechanisms and the isomers in the dominant reaction classes of the fuel-specific sub-mechanism were lumped. The scale of the final mechanism was reduced further by removing the unimportant reactions in the important small-molecule sub-mechanism, and the initial reduced mechanism was obtained. Final, the optimization of the reaction rate constants in the fuel-specific sub-mechanism was performed under their uncertainties to improve the performance of the reduced mechanism over a wide temperature range. With the proposed method, a detailed iso-cetane mechanism including 1107 species and 4469 reactions was reduced. The reduced mechanism contains only 56 species and 131 reactions. Good agreements between the reduced mechanism and the detailed mechanism were achieved on the predicted results of ignition delay times and species concentrations over wide conditions.

中文翻译：

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使用反应类/子机制的全局敏感性分析减少大规模化学机制

摘要 具有紧凑尺度的可靠化学机理在发动机建模中起着重要作用。在这项研究中，通过对详细机制中反应类别/子机制的全局敏感性分析，提出了一种减少大规模反应动力学机制的新方法。在本方法中，首先使用莫里斯方法评估每个反应子机制在详细机制中的重要性。然后，使用莫里斯方法和路径敏感性分析，基于它们对详细机理预测的重要性及其耦合关系，确定了燃料特定子机理中的关键反应类别。第三，不重要的子机制中的反应和燃料特定子机制的主要反应类别中的异构体被归为一类。通过去除重要的小分子子机理中不重要的反应，进一步缩小最终机理的规模，得到最初的简化机理。最后，在不确定性下对燃料特定子机制中的反应速率常数进行优化，以提高简化机制在较宽温度范围内的性能。使用所提出的方法，减少了包括 1107 个物种和 4469 个反应的详细异十六烷机制。简化机制仅包含 56 个物种和 131 个反应。在广泛条件下点火延迟时间和物种浓度的预测结果上，简化机制和详细机制之间取得了良好的一致性。