Computational and Experimental Study of Oxygenated Hydrocarbon Fuel Chemistry in Non-premixed Flames

1133211 Pfefferle智力优点：植物中约有50%的氧气重量。 因此，随着社会不可避免地从化石燃料转向可再生燃料，燃烧燃料的氧含量将增加。 燃料中含氧碳氢化合物的存在引入了重要的燃烧科学和公共卫生问题，这些问题由拟议的研究解决。 首先，含氧化合物可以减少烟灰颗粒的排放。 其次，它们还可以增加其他有毒燃烧副产物如醛类的排放。 为了合理优化碳烟减排，同时最大限度地减少空气中有毒物质的排放，我们需要了解含氧化合物的燃料分解和芳烃形成的化学机制。从植被中可以得到的含氧化合物的数量很大，并且炭黑的倾向和燃料分解产物作为碳结构的函数变化很大;因此，严格的经验方法在其中进行选择是不可靠的。需要一种分析大量含氧燃料并导致可以从燃料结构预测机制和反应性的方法的策略。虽然烃和一些小的含氧化合物的燃烧化学已被广泛研究，但对大多数含氧烃知之甚少。 我们提出了一种新的方法，该方法是基于快速，在线物种测量和计算模拟的并流火焰中，少量的含氧燃料添加到甲烷的基础燃料。基础甲烷火焰的特点是，计算提供了良好的协议与实验物种的测量。 我们的策略涉及扰动的一个良好的特征系统，使高质量的测量，也有利于模拟，因为从以前计算的基础甲烷火焰的解决方案可以用作所有的掺杂火焰的起始估计。重要的是，我们的方法比较了相同的火焰条件下的含氧燃料物种的命运，强调在化学机制的差异超过其他factors.In早期的工作，我们验证了这种方法的常规烃，包括庚烷，己烯，己二烯，环烷烃和芳烃。在这里，我们将把它扩展到100+含氧碳氢化合物，最多20个碳原子。我们的研究结果将提供一个重要的比较含氧化合物燃烧化学的其他研究，其中大多数使用预混火焰和有限数量的含氧燃料结构。 需要对各种结构进行分析，以建立结构/反应性关系，从而进行可靠的机理测试，并为选择含氧燃料提供合理的依据，以优化排放效益。我们的工作通过将数据库扩展到含氧碳氢化合物，并为燃料结构对碳烟生成和可能的有毒含氧排放的影响提供了合理的关联和外推数据。我们将与当地企业合作，以促进这一点。 我们已经向世界各地的许多团体提供了我们以前研究的详细结果，这些团体已经使用它们来测试计算模型。 这里生成的数据库将被存档，供世界各地的研究人员直接访问。本科生参加了我们以前的研究，并将执行与本项目相关的实验室模块。我们还将让当地非博士授予学院和高中的学生参与我们的工作，帮助他们在家乡机构开发研究项目，并使他们对继续学习科学感兴趣。

1133211PfefferleIntellectual Merit: Plants are about 50 % oxygen by weight. Thus as society inevitably moves from fossil fuels towards renewable fuels, the oxygen content of combustion fuels will increase. The presence of oxygenated hydrocarbons in the fuel introduces important combustion science and public health issues that are addressed by the proposed research. First, oxygenates may reduce emissions of soot particles. Second, they can also increase emissions of other toxic combustion byproducts such as aldehydes. In order to rationally optimize soot reductions while minimizing air toxics emissions, we need to understand the chemical mechanisms of fuel decomposition and aromatic hydrocarbon formation for oxygenates. The number of oxygenates that can be made from vegetation is large, and the sooting tendencies and fuel decomposition products vary greatly as a function of oxygenate structure; thus strictly empirical approaches for choosing among them are not reliable. A strategy that analyzes a large number of oxygenated fuels and leads to methods that can predict mechanisms and reactivity from fuel structure is needed. Although the combustion chemistry of hydrocarbons and some small oxygenates has been widely studied, little is known for most oxygenated hydrocarbons. We propose a novel approach that is based on rapid, on-line species measurements and computational simulations in co-flow flames where a small amount of the oxygenated fuel is added to a base fuel of methane. The base methane flame is has been well characterized and computations provide good agreement with experimental species measurements. Our strategy involving perturbation of a well-characterized system enables high-quality measurements and also facilitates simulations because the solutions from previously computed base methane flames can be used as a starting estimate for all of the doped flames. Importantly, our methods compare the fate of oxygenated fuel species under identical flame conditions emphasizing differences in chemical mechanisms over other factors.In earlier work we validated this methodology for regular hydrocarbons including heptanes, hexenes, hexadienes, cycloalkanes and aromatics. Here we will extend it to 100+ oxygenated hydrocarbons with up to 20 carbon atoms. Our results will provide an important comparison to other studies of oxygenates combustion chemistry, most of which use premixed flames and a limited number of oxygenated fuel structures. The analysis of a wide range of structures is required for development of structure/reactivity relationships allowing robust mechanism testing and a rational basis for oxygenated fuel selection to optimize emissions benefits.Broader Impacts: Our work sets the stage for cleaner engine design and renewable fuels utilization by expanding the database to oxygenated hydrocarbons, and by providing rational correlation and extrapolation data for the effect of fuel structure on soot production and possible toxic oxygenated emissions. We will collaborate with local industry to facilitate this. We have provided detailed results from our previous studies to numerous groups around the world who have used them to test computational models. The databases generated here will be archived for direct access to researchers around the world. Undergraduate students have participated in our previous research and will perform laboratory modules related to this project. We will also involve students from local non-PhD granting colleges and high schools in our work and helping them develop research projects at their home institutions and to interest them in continuing study in the sciences.