Fuel Decomposition and Aromatic Formation Pathways for the Hydrocarbons Contained in Liquid Combustion Fuels

CTS-0457452获奖液体燃烧炉中所含碳氢化合物的分解和芳香形成途径Soot纳米颗粒和燃烧室排放的芳香烃对全球环境有害，并构成公共健康风险。了解火焰中燃料分解和芳香烃形成的化学机理对于合理减少这些排放是很重要的。尽管人们对小碳氢化合物的这种化学作用进行了广泛的研究，但对构成大多数液体燃烧燃料的大碳氢化合物却知之甚少。这一建议提出了一种新的方法，基于火焰中的实验测量，其中将少量被研究的物种添加到具有良好特性的甲烷火焰中。这使得可以直接研究这些大分子碳氢化合物的化学。在早期的工作中，我们验证了这一方法，并将其应用于C5到C7碳氢化合物；结果表明，i)大的碳氢化合物可以访问经过充分研究的较小的碳氢化合物没有的途径，ii)这些途径可以控制碳烟纳米颗粒的产生。这项拟议研究的目标是阐明典型液体燃料中存在的碳氢化合物的燃料分解和芳香烃形成。我们的化学物种测量技术是快速和在线的，因此可以在合理的时间内获得各种燃料成分的详细物种图。这些广泛的数据使我们能够在开发反应机理测试时利用物种特征的差异。结果将通过从掺杂剂分布中提取分解率，检查芳烃与其可能的前体之间的相关性，以及通过计算模拟来分析。更广泛的影响：我们的工作为更清洁的发动机设计奠定了基础，扩大了大型碳氢化合物化学反应性的数据库，并为燃料结构对反应性的影响提供了合理的关联和外推数据。我们已经向世界各地的许多小组提供了我们目前研究的详细实验结果，他们使用这些结果来测试计算模型。在拟议研究期间产生的数据库将可通过互联网直接下载。这一分析的结论将有助于开发能够预测实际燃烧室中纳米颗粒形成的定量计算机模型，以及减少实际燃烧室的碳烟排放的策略。本科生一直是我们研究的关键组成部分，他们将完成与该项目相关的课程实验室模块。

CTS-0457452 AWARD ABSTRACTFUEL DECOMPOSITION AND AROMATIC FORMATION PATHWAYS FOR THE HYDROCARBONS CONTAINED IN LIQUID COMBUSTION FUELSSoot nanoparticle and aromatic hydrocarbon emissions from combustors are harmful to the global environment and pose public health risks. An understanding of the chemical mechanisms of fuel decomposition and aromatic hydrocarbon formation in flames is important for a rational approach to reduce these emissions. Although such chemistry has been studied extensively for small hydrocarbons, little is known for the larger hydrocarbons that constitute most liquid combustion fuels. This proposal presents a novel approach, based on experimental measurements in flames where a small amount of the species to be studied is added to a well characterized methane flame. This allows the chemistry of these large hydrocarbons to be studied directly. In earlier work we validated this methodology and applied it to C5 to C7 hydrocarbons; the results showed that i) large hydrocarbons can access pathways not available to the well-studied smaller hydrocarbons and ii) these pathways can control soot nanoparticle production. The goal of this proposed research is to elucidate fuel decomposition and aromatic hydrocarbon formation for hydrocarbons present in typical liquid fuels. Our chemical species measurement techniques are rapid and on-line so detailed species maps can be obtained for a wide range of fuel components in a reasonable time. This wide range of data allows us to exploit the differences in the species profiles in developing reaction mechanism tests. Results will be analyzed by extracting decomposition rates from the dopant profiles, examining the correlation between aromatics and their possible precursors, and by computational simulation. Broader Impact: Our work sets the stage for cleaner engine design by expanding the database for the chemical reactivity of large hydrocarbons and by providing rational correlation and extrapolation data for the effect of fuel structure on reactivity. We have provided detailed experimental results from our current studies to numerous groups around the world who have used them to test computational models. The databases generated during the proposed research will be available for direct downloading over the internet. The conclusions from this analysis will facilitate the development of quantitative computer models that can predict nanoparticle formation in practical combustors and of strategies for reducing soot emissions from practical combustors. Undergraduate students have been a key component in our research and will perform course laboratory modules related to this project.