Automatic identification and lumping of high-temperature fuel decomposition pathways for chemical kinetics mechanism reduction
Automatic identification and lumping of high-temperature fuel decomposition pathways for chemical kinetics mechanism reduction
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DOI：
10.1016/j.proci.2020.06.328
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
Lara Heberle;P. Pepiot
中科院分区：
文献类型：
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作者：
Lara Heberle;P. Pepiot
燃烧系统计算流体动力学 (CFD) 的预测能力依赖于对燃料化学的正确描述。人们对准确捕获多组分燃料混合物的燃烧行为越来越感兴趣，这为开发足够小以用于 CFD 的降阶化学动力学机制带来了额外的挑战。在一系列可用的化学还原方法中，集总技术似乎特别适合处理多组分燃烧化学的复杂性质。特别是，已发表的文献提供了非常有力的证据，证明非限速途径的集总，更具体地说，高温燃料分解反应，是多组分机制还原的有力途径。在这项工作中，我们提出了一种新颖的算法，可以从详细的动力学机制中识别和集中高温燃料分解反应。集中策略是全自动的，并且完全依赖于详细机制中可用的信息。该技术的性能针对单组分燃料正十二烷及其与异辛烷的混合物进行了评估。结果表明，用涉及单一等效燃料成分的少量反应代替燃料分解子机制，对层流火焰速度、点火延迟曲线和物质分布的预测带来的变化非常有限。这为所提出的算法奠定了明显的潜力，可以成为现有多阶段机制简化软件的有价值的补充。
The predictive capabilities of Computational Fluid Dynamics (CFD) for combustion systems rely on a proper description of the fuel chemistry. The growing interest in accurately capturing the combustion behavior of multi-component fuel mixtures creates additional challenges in developing reduced-order chemical kinetics mechanisms small enough to be used in CFD. Among the suite of chemistry reduction approaches available, lumping techniques appear especially suited to handle the complex nature of multi-component combustion chemistry. In particular, published literature provides very strong evidence that the lumping of non-rate-limiting pathways, and more specifically, the high-temperature fuel decomposition reactions, is a powerful avenue for multi-component mechanism reduction. In this work, we present a novel algorithm to identify and lump high temperature fuel decomposition reactions from detailed kinetic mechanisms. The lumping strategy is fully automatic, and relies exclusively on information available in the detailed mechanism. The performance of the technique is assessed for both a single-component fuel,n-dodecane, and its mixture withiso-octane. Results show that replacing the fuel decomposition sub-mechanism by a small number of reactions involving a single equivalent fuel component introduces very limited changes in the prediction of laminar flame speeds, ignition delay curves, and species profiles. This establishes a clear potential for the proposed algorithm to become a valuable addition to existing multi-stage mechanism reduction software.