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

非预混火焰中含氧烃燃料化学的计算和实验研究

• 批准号: 1133211
• 负责人: Lisa Pfefferle
• 金额: $ 32.5万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1133211&HistoricalAwards=false
• 关键词: Computational; Experimental; Study; Oxygenated; Hydrocarbon

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.

1133211Pfefferle智力优点：按重量计算，植物含有约 50% 的氧气。 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会增加。 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，这些问题是由拟议的研究解决的。 首先，含氧化合物可以减少烟灰颗粒的排放。 其次，它们还会增加其他有毒燃烧副产物（例如醛）的排放。 为了合理优化烟灰减排，同时最大限度地减少空气有毒物质排放，我们需要了解燃料分解和含氧化合物芳烃形成的化学机制。由植被产生的含氧化合物的数量很大，并且烟灰倾向和燃料分解产物随着含氧化合物结构的变化而变化很大；因此，在它们之间进行选择的严格经验方法是不可靠的。需要一种分析大量含氧燃料并找到可以根据燃料结构预测机制和反应性的方法的策略。尽管碳氢化合物和一些小型含氧化合物的燃烧化学已被广泛研究，但对于大多数含氧碳氢化合物却知之甚少。 我们提出了一种基于快速在线物种测量和并流火焰计算模拟的新颖方法，其中将少量含氧燃料添加到甲烷基础燃料中。基础甲烷火焰已得到很好的表征，计算结果与实验物种测量结果吻合良好。 我们的策略涉及对一个良好表征的系统进行扰动，从而实现高质量的测量，并且还有助于模拟，因为之前计算的基础甲烷火焰的解决方案可以用作所有掺杂火焰的起始估计。重要的是，我们的方法比较了含氧燃料物种在相同火焰条件下的命运，强调了化学机制相对于其他因素的差异。在早期的工作中，我们针对常规碳氢化合物（包括庚烷、己烯、己二烯、环烷烃和芳烃）验证了这种方法。在这里，我们将其扩展到 100 多种含最多 20 个碳原子的含氧烃。我们的结果将为含氧化合物燃烧化学的其他研究提供重要的比较，其中大多数研究使用预混合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，以开发结构/反应性关系，从而进行稳健的机制测试和含氧燃料选择的合理基础，以优化排放效益。更广泛的影响：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产生的影响提供合理的相关性和外推数据，为更清洁的发动机设计和可再生燃料的利用奠定了基础 以及可能的有毒含氧化合物排放。我们将与当地工业界合作以促进这一点。 我们已向世界各地的许多团体提供了之前研究的详细结果，他们使用这些结果来测试计算模型。 这里生成的数据库将被存档，以便世界各地的研究人员直接访问。本科生参与了我们之前的研究，并将执行与该项目相关的实验室模块。我们还将让当地非博士学位授予大学和高中的学生参与我们的工作，帮助他们在本国机构开发研究项目，并激发他们继续学习科学的兴趣。