Plasma-based global pathway analysis to understand the chemical kinetics of plasma-assisted combustion and fuel reforming
Plasma-based global pathway analysis to understand the chemical kinetics of plasma-assisted combustion and fuel reforming
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DOI：
10.1016/j.combustflame.2023.112927
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发表时间：
2023-09
影响因子：
4.4
通讯作者：
Praise N. Johnson;Taaresh S. Taneja;Suo Yang
中科院分区：
文献类型：
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作者：
Praise N. Johnson;Taaresh S. Taneja;Suo Yang
摘要 全局路径分析 (GPA) 算法通过识别通过各种重要中间物种（即中心物种）将源物种与汇物种连接的重要全局反应路径，帮助分析复杂燃烧系统的化学动力学。目前的工作旨在将 GPA 算法扩展到等离子体辅助燃烧和燃料重整系统，以识别此类系统在各种条件下的主要全局路径。此外，本研究扩展了 GPA 算法识别反应循环的能力，该反应循环涉及将高浓度物质（例如 O 2、N 2 和燃料）激发到其振动和电子状态，以及随后去激发到其基态，基于它们对等离子体辅助系统在气体加热和自由基产生方面的反应性的重要性。 GPA 算法中规定，根据元素通量转移（即优势）、热释放和自由基生产率来评估已识别反应途径和循环的反应性。然后使用新开发的基于等离子体的全局路径分析（PGPA）算法来分析氨的等离子体辅助燃烧和甲烷的重整。 PGPA 分析阐明了振动平移循环对NH 3 /空气混合物反应性的重要性。此外，对NO产生的分析将NH 3 早期重整为N 2 和H 2 ，这阻碍了等离子体辅助NH 3 点火过程中NO的产生。最后，与热重整相比，使用等离子体对CH 4/N 2 混合物的增强重整归因于CH 4 的电子碰撞解离。相比之下，传统的路径通量分析 (PFA) 需要大量的手动工作和来自专业知识的预分析直觉，因此很难提供有关等离子体化学的有价值的见解。因此，PGPA 的用户友好性和自动化特性为评估等离子体辅助系统的动力学提供了一个有价值的工具，有助于分析，并进一步为减少等离子体辅助化学奠定了基础，而无需专业知识。
Abstract The Global Pathway Analysis (GPA) algorithm helps analyze the chemical kinetics of complex combustion systems by identifying important global reaction pathways connecting a source species to a sink species through various important intermediate species (ie, hub species). The present work aims to extend GPA algorithm to plasma-assisted combustion and fuel reforming systems to identify the dominant global pathways in such systems at various conditions. In addition, the present study extends the ability of GPA algorithm to identify reaction cycles involving the excitation of high-concentration species (eg, O 2, N 2, and fuel) to their vibrational and electronic states and the subsequent de-excitation to their ground state, based on their significance on the reactivity of plasma-assisted systems in terms of gas heating and radical production. Provisions are made in the GPA algorithm to evaluate the reactivity of identified reaction pathways and cycles based on the element-flux transfer (ie, dominance), heat release, and radical production rate. The newly developed Plasma-based Global Pathway Analysis (PGPA) algorithm is then used to analyze the plasma-assisted combustion of ammonia and reforming of methane. The PGPA analyses elucidated the significance of vibrational-translational cycles on the reactivity of NH 3/air mixtures. Further, analyses on the production of NO ascribed the early reforming of NH 3 to N 2 and H 2 in impeding the production of NO during plasma-assisted NH 3 ignition. Lastly, the enhanced reforming of CH 4/N 2 mixtures using plasma has been attributed to electron impact dissociation of CH 4 when compared to thermal reforming. In contrast, conventional path-Flux analysis (PFA) was found to require significant manual effort and pre-analysis intuitions from expert knowledge, making it arduous to provide valuable insights into plasma chemistry. The user-friendly and automated nature of PGPA thus provides a valuable tool for assessing the kinetics of plasma-assisted systems helpful in analyzing and, further, a foundation in reducing plasma-assisted chemistry, without the needs of expert knowledge.