EAGER: A Shock Tube Study of Laminar Flames in Transportation Fuels at Engine Relevant Temperatures

该项目旨在开发新的实验技术，用于研究与交通系统相关的条件下的火焰。目前，实验的局限性阻碍了对现代火花点火和喷气发动机中高温预混火焰的研究。通过使用激波管，这项工作旨在克服这些实际限制，并使未来的实验研究能够在与现代发动机最相关的条件下进行。还将开展探索性工作，以了解仅存在于高温火焰中的独特结构。这项工作将共同支持清洁高效发动机的开发，以实现减少空气污染、控制与交通相关的温室气体排放和限制对外国化石燃料的依赖等关键目标。这个项目的两个主要目标中的第一个是改进最近在汉森实验室演示的激波管火焰速度方法。激波管中的快速加热和静止的激波后条件允许在以前无法接触到的温度下启动和研究球形膨胀的火焰。将进一步改进和验证这一方法，以优化实验和数据处理方法，以确保使用该方法产生的高温火焰数据符合科学界和工程界的高质量标准。第二个主要目标是使用各种基于激光和成像的诊断方法来研究在高温下观察到的特殊火焰结构。模拟和初步实验证据都表明，在高温下可以观察到两级火焰，其中冷火焰先于经典的热火焰。这一现象将进行实验研究，这一目标将利用激波管在高温下产生火焰的独特能力和汉森实验室现有的光学诊断专业知识。用于研究高温火焰结构的诊断学可能包括视线激光吸收、平面激光诱导荧光和光谱过滤发射成像。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project aims to develop novel experimental techniques for studying flames at conditions relevant to transportation systems. Currently, experimental limitations prevent the study of premixed flames at the high-temperatures found in modern spark-ignition and jet engines. By using shock tubes, this work aims to overcome those practical limits and allow future experimental studies to be conducted at the conditions most relevant to modern engines. Exploratory work will also be undertaken to understand unique structures only present in high-temperature flames. Together, this work will support the development of the clean and efficient engines needed to meet the critical goals of reducing air pollution, reigning in transportation-related greenhouse gas emissions, and limiting dependence on foreign fossil fuels. The first of two major goals of this project is to refine the shock-tube flame speed method recently demonstrated in the Hanson laboratory. The rapid heating and quiescent post-shock conditions in a shock tube allow for spherically expanding flames to be initiated and studied at previously inaccessible temperatures. This method will be further refined and validated to optimize experimental and data-processing methods in order to ensure that high-temperature flame data produced using the method meets the high quality standards of the scientific and engineering communities. The second major goal is to use a variety of laser- and imaging-based diagnostics to study peculiar flame structures observed at high temperatures. Both simulations and preliminary experimental evidence suggest that two-stage flames, with a cool flame preceding the classical hot flame, may be observed at high temperatures. This phenomenon will be experimentally investigated, an objective that will leverage both the unique ability to generate flames at high temperatures afforded by the shock tube and the existing optical diagnostic expertise of the Hanson lab. Diagnostics to be employed in the study of high-temperature flame structure are likely to include line-of-sight laser absorption, planar laser-induced fluorescence, and spectrally filtered emission imaging.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.