EAGER/CEMOR: A New Diagnostic for Quantitative Measurement of HO2 and RO2

EAGER/CEMOR：HO2 和 RO2 定量测量的新诊断方法

• 批准号: 1142312
• 负责人: Nicholas Cernansky
• 金额: $ 6万
• 依托单位: Drexel 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: 2011-07-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1142312&HistoricalAwards=false
• 关键词: EAGER; CEMOR; New; Diagnostic; Quantitative

1142312 CernanskyImplementing new engine designs that operate utilizing Low Temperature Combustion (LTC) has been identified as key to lowering emissions, enhancing efficiency and thereby reducing the dependency of the United States on foreign sources of fuel. Unfortunately, the chemistry models describing LTC are inadequate to proceed with these designs and, while the best theories suggest that LTC is controlled by hydroperoxy radical (HO2) and alkylperoxy radical (RO2), these species are not readily measured in engines and other combustion systems by existing methodologies. Quantitative measurement of these radicals and development of LTC chemistry models will significantly shorten the time to implement the benefits of LTC. This program is focused on demonstrating that cavity enhanced magneto-optical rotation (CEMOR), a highly sensitive and selective laser diagnostic technique developed at Drexel University, can be applied for in situ measurement of HO2 and RO2 in reaction systems. CEMOR combines the sensitivity of cavity ringdown spectroscopy (CRDS) with the selectivity of magneto optic rotation (MOR) to provide selective detection of weakly absorbing species in complex reacting environments. We have shown in our laboratory that CEMOR allows selective observation of paramagnetic species, simplifying detection in otherwise complicated mixtures, and we also have made the first measurements of a radical, OH, in a lean premixed methane/air flame using MOR and CEMOR. These results demonstrate the effectiveness of measuring combustion generated radicals using the MOR and CEMOR techniques, and illustrates the increase in sensitivity CEMOR exhibits over MOR. The next step is to measure HO2 in the controlled environment of a photolysis cell using both CRDS and CEMOR in order to generate high resolution absorption cross section data and to calibrate the CEMOR technique for the subsequent demonstration of quantitative measurements in a combustion environment. Intellectual Merit Application of CEMOR for in situ measurements of HO2 and RO2 radicals will provide new insight into the reaction dynamics of low and intermediate temperature combustion systems. This will aid in the design of the next generation engine systems that use this reaction regime to achieve increased efficiency and reduced emissions. This new measurement capability also will be useful in other areas (e.g., atmospheric chemistry) where highly sensitive and selective peroxy radical measurements are desired. Broader Impact The societal impact of transitioning to engine designs employing low temperature combustion technologies could be enormous, and this research will provide an important tool to help enable such a transition. As such, the research is both appropriate and needed. The educational impact of the research will be through providing an opportunity to train students in optical diagnostics and combustion science, giving them the required skills to contribute to the combustion/energy community. One graduate research assistant will be supported by this project, and one or two undergraduate students are expected to participate in this project as part of our Honors Research Program experience. Special attention will be given to attracting underrepresented minority and female students building on successful programs existing at Drexel University. The results of the research will be presented as professional presentations, archival publications, website entries, and theses/dissertations, providing other researchers and the public with the information needed to understand newly important combustion processes.

实施利用低温燃烧（LTC）运行的新发动机设计已被确定为降低排放，提高效率，从而减少美国对外国燃料来源的依赖的关键。不幸的是，描述LTC的化学模型不足以进行这些设计，虽然最好的理论表明，LTC是由氢过氧自由基（HO 2）和烷基过氧自由基（RO 2）控制，这些物种是不容易测量发动机和其他燃烧系统通过现有的方法。这些自由基的定量测量和LTC化学模型的开发将大大缩短实现LTC益处的时间。该计划的重点是证明腔增强磁光旋转（CEMOR），一个高灵敏度和选择性的激光诊断技术在德雷克塞尔大学开发，可用于原位测量反应系统中的HO 2和RO 2。CEMOR结合了光腔衰荡光谱（CRDS）的灵敏度和磁光旋转（莫尔）的选择性，能够在复杂的反应环境中对弱吸收物质进行选择性检测。我们已经表明，在我们的实验室中，CEMOR允许选择性地观察顺磁性物质，简化检测，否则复杂的混合物，我们也取得了第一次测量的自由基，OH，在贫预混甲烷/空气火焰使用莫尔和CEMOR。这些结果证明了使用莫尔和CEMOR技术测量燃烧产生的自由基的有效性，并说明了CEMOR表现出的灵敏度超过莫尔的增加。 下一步是使用CRDS和CEMOR在光解池的受控环境中测量HO 2，以生成高分辨率吸收截面数据，并校准CEMOR技术，用于随后在燃烧环境中进行定量测量的演示。 CEMOR用于原位测量HO 2和RO 2自由基的智能优点应用将为中低温燃烧系统的反应动力学提供新的见解。 这将有助于下一代发动机系统的设计，这些系统使用这种反应机制来实现提高效率和减少排放。 这种新的测量能力在其他领域也将是有用的（例如，大气化学），其中需要高灵敏度和选择性的过氧自由基测量。 向采用低温燃烧技术的发动机设计过渡的社会影响可能是巨大的，这项研究将提供一个重要的工具来帮助实现这种过渡。 因此，这项研究是适当的，也是必要的。 该研究的教育影响将通过提供机会来培训学生光学诊断和燃烧科学，使他们具备为燃烧/能源社区做出贡献所需的技能。 一个研究生研究助理将支持这个项目，一个或两个本科生预计将参加这个项目作为我们的荣誉研究计划的经验的一部分。 将特别注意吸引代表性不足的少数民族和女性学生在德雷克塞尔大学现有的成功计划的基础上建设。 研究结果将以专业演讲、档案出版物、网站条目和论文/学位论文的形式呈现，为其他研究人员和公众提供了解新的重要燃烧过程所需的信息。