Soot-based Global Pathway Analysis: Soot formation and evolution at elevated pressures in co-flow diffusion flames,Combustion and Flame

当前位置： X-MOL 学术 › Combust. Flame › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Soot-based Global Pathway Analysis: Soot formation and evolution at elevated pressures in co-flow diffusion flames
Combustion and Flame ( IF 5.8 ) Pub Date : 2021-01-18 , DOI: 10.1016/j.combustflame.2021.01.007
Dezhi Zhou , Suo Yang

One of the major concerns in high pressure combustion is its high soot yield. An exact and comprehensive mechanism behind this phenomenon, from a chemical kinetics perspective, is still elusive. In this study, a series of pressurized (1–16 atm) co-flow ethylene diffusion sooting flames are simulated with detailed finite-rate chemistry and molecular transport. The experimental maximum soot volume fraction and its scaling law with pressure are well reproduced by the simulations. To extract kinetic information from the complex sooting reacting system, a Soot-based Global Pathway Analysis (SGPA) method is developed to identify the dominant Global Pathways (GPs) from fuel to soot by considering carbon element flux from gaseous species to soot. Using SGPA, the dominance and sensitivity of soot chemical pathways at elevated pressures are revealed. It is found that increasing pressure shifts the first ring Polycyclic Aromatic Hydrocarbon (PAH) formation from C $_{3}$ H $_{3}$ recombination to reactions involving C $_{2}$ H $_{2}$ . At 1 atm, the production of C $_{2}$ H $_{2}$ for surface growth is purely controlled by the H-abstraction of C $_{2}$ H $_{4}$ and C $_{2}$ H $_{3}$ . In contrast, at elevated pressures, the production of C $_{2}$ H $_{2}$ for surface growth is also influenced by many other reactions including some third body reactions. The SGPA method reveals that the mismatch of predicted PAH with the experimental data at 12 atm is majorly caused by the rate coefficient uncertainty of the reaction C $_{2}$ H $_{2}$ + A1CH $_{2}$ = C $_{9}$ H $_{8}$ + H. Based on the analysis by SGPA, the mechanism reduction based on Directed Relation Graph with Error Propagation (DRGEP) with A2 and C $_{2}$ H $_{2}$ as the target species deleted significant species such as C $_{9}$ H $_{8},$ C $_{9}$ H $_{7},$ incurring inaccurate soot field prediction. It is also found that the combined dominance of GPs with heavier PAH species (A4-A7) is even greater than the most dominant GP at the flame wing regions, indicating that heavier PAH species play critical roles for soot nucleation and condensation, especially at the flame wing regions.

中文翻译：

基于烟尘的全球路径分析：在高压下，并流扩散火焰中烟尘的形成和演化

高压燃烧的主要问题之一是其高烟灰收率。从化学动力学的角度来看，这种现象背后的确切而全面的机制仍然难以捉摸。在这项研究中，用详细的有限速率化学和分子传输模拟了一系列加压（1-16 atm）同流乙烯扩散烟灰火焰。通过模拟可以很好地再现实验得出的最大烟灰体积分数及其随压力的缩放规律。为了从复杂的碳烟反应系统中提取动力学信息，开发了一种基于碳烟的全球路径分析（SGPA）方法，通过考虑从气态物质到碳烟的碳元素通量来识别从燃料到碳烟的主要全球路径（GPs）。使用SGPA，揭示了烟灰化学途径在高压下的优势和敏感性。 $_{3}$ H $_{3}$ 重组为涉及C的反应 $_{2}$ H $_{2}$ 。在1个大气压下生产C $_{2}$ H $_{2}$ 表面生长完全由C的H吸收控制 $_{2}$ H $_{4}$ 和C $_{2}$ H $_{3}$ 。相反，在高压下，C的产生 $_{2}$ H $_{2}$ 表面生长也受到许多其他反应的影响，包括一些第三者的反应。SGPA方法揭示了预测的PAH与12 atm的实验数据的不匹配主要是由反应C的速率系数不确定性引起的 $_{2}$ H $_{2}$ + A1CH $_{2}$ = C $_{9}$ H $_{8}$ + H.根据SGPA的分析，基于带有错误传播的有向关系图（DRGEP）和A2和C的机构简化 $_{2}$ H $_{2}$ 因为目标物种删除了重要物种，例如C $_{9}$ H $_{8} ，$ C $_{9}$ H $_{7} ，$ 产生不准确的烟尘场预测。还发现GP与重PAH种类（A4-A7）的组合优势甚至大于火焰翼区域最显性的GP，这表明重PAH种类对于烟尘成核和凝结起着关键作用，尤其是在烟灰区。火焰翼区域。

更新日期：2021-01-19

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11