Mechanism optimization based on reaction rate rules
Mechanism optimization based on reaction rate rules
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DOI：
10.1016/j.combustflame.2013.08.024
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发表时间：
2014-02-01
影响因子：
4.4
通讯作者：
Pitsch, Heinz
中科院分区：
文献类型：
--
作者：
Cai, Liming;Pitsch, Heinz
准确的化学模型构成了用于模拟复杂燃烧装置的详细计算流体动力学 (CFD) 工具的支柱。燃烧化学通常非常复杂，化学机制通常涉及一百多种物质和一千种反应。在这些大型化学机理的推导过程中，通常会出现大量反应，而这些反应的速率数据无法从实验或理论中获得。然后，通常使用所谓的反应类别来分配这些反应的速率数据。该方法将所有可能的燃料特定反应分类为具有规定的速率常数规则的反应类别。这确保了化学机制的一致性。在已发表文献中发现的速率参数优化中，通常系统地优化单个基元反应的速率常数，以实现模型性能和实验测量之间的良好一致性。然而，修改单个反应的速率参数在动力学上是不合理的，因为这会违反动力学相似反应的速率参数的一致性。在这项工作中，校准了确定反应类别速率的速率规则，而不是单个基本反应的速率，从而实现了化学上更加一致的模型优化。这是通过优化正戊烷燃烧机制来证明的。研究了反应类别、抽象物质、断裂的 C-H 键和环应变能垒等方面的速率规则。此外，速率规则和模型预测的不确定性被最小化，并且主导低温氧化的反应类别的压力依赖性被优化。 (C) 2013 年燃烧研究所。由爱思唯尔公司出版。保留所有权利。
Accurate chemistry models form the backbone of detailed computational fluid dynamics (CFD) tools used for simulating complex combustion devices. Combustion chemistry is often very complex and chemical mechanisms generally involve more than one hundred species and one thousand reactions. In the derivation of these large chemical mechanisms, typically a large number of reactions appears, for which rate data are not available from experiment or theory. Rate data for these reactions are then often assigned using so-called reaction classes. This method categorizes all possible fuel-specific reactions as classes of reactions with prescribed rules for the rate constants. This ensures consistency in the chemical mechanism. In rate parameter optimizations found in the published literature, rate constants of single elementary reactions are usually systematically optimized to achieve good agreement between model performance and experimental measurements. However, it is not kinetically reasonable to modify the rate parameters of single reactions, because this will violate consistency of rate parameters of kinetically similar reactions. In this work, the rate rules, that determine the rates for reaction classes are calibrated instead of the rates of single elementary reactions leading to a chemically more consistent model optimization. This is demonstrated by optimizing an n-pentane combustion mechanism. The rate rules are studied with respect to reaction classes, abstracting species, broken C-H bonds, and ring strain energy barriers. Furthermore, the uncertainties of the rate rules and model predictions are minimized and the pressure dependence of reaction classes dominating low temperature oxidation is optimized. (C) 2013 The Combustion Institute. Published by Elsevier Inc. All rights reserved.