BRIGE: Combustion Intermediate Species Measurement Using Microwave and Laser Diagnostics

1032523张这项扩大参与研究启动助学金工程(Brige)计划的总体目标是创造新的微波和激光诊断技术，用于在大气压和更高压力下对化石燃料和生物燃料燃烧中的中间物种进行定量测量，并教育学生基础激光物理、燃烧科学和能源相关技术。目前，化石燃料的燃烧提供了全球约85%的能源消耗，并产生了大部分空气污染物。生物燃料是一种可替代的可再生能源，它的燃烧可以减少一些污染物的排放。原则上，所有燃料的燃烧都要经过许多基本的反应步骤。原子、分子自由基和复杂分子物种在控制化学过程网络中起着主导作用，其中许多物种在现有的诊断技术中并不能很好地理解，因为这些物种大多是瞬时的，而且浓度很低。特别是，由于极其复杂的化学过程，人们对生物燃料燃烧的了解很少，这对诊断工具的局限性提出了挑战，使数值模拟变得异常困难。利用新的诊断技术对化石燃料和生物燃料燃烧中的中间化合物及其反应进行系统的研究，可能会导致更节能、更环保的设备和设施的革命性发展，有助于解决全球气候变化等经济和社会问题。这项研究的智能价值在于新的微波和激光诊断技术，来自局域共振增强多光子电离的共振相干微波散射(REMPI)和分子在里德堡态的光离将被用来识别火焰区域内和周围的中间痕量物种，灵敏度在~100 ppb(百万分之一)水平。后续的物种包括H和O原子，CH3和HCO自由基，以及复杂的异构体分辨分子C6H6和C7H8等。该技术使用一到两个频率可调的激光选择性地产生特定物种的电离，并利用共振相干微波散射来定量检测通过电离区内的电子的物种浓度的演变。这些特点结合在一起，提供了一种高精度、淬灭耐用的电离光谱，可以在压力高达工作燃烧室压力的情况下实时定量测量物种的浓度。新诊断技术在中间组分测量中的应用将极大地促进我们对基本燃烧现象的理解。对特定条件下的生物燃料燃烧进行系统的诊断评估将提供基本的物种信息，可用于验证和校准现有的生物燃料燃烧化学动力学模型，从而可能导致更高的燃烧效率和更多用途、更少污染的生物燃料来源和装置。广泛影响拟议的研究将开发一种新的能力，可能对许多工程领域产生广泛的影响，如航空航天、机械、交通和其他依赖燃烧的工业。与计划的研究相辅相成的是一项详细的教育计划，该计划将对教育下一代劳动力产生广泛影响，并将对广泛的社区教育产生积极影响的外联努力。作为拟议的教育努力的一部分，国际和平研究所将直接根据这项研究开发两门课程。实验室工作将为课程设计，以促进更开放的工程教育方法，在此基础上，学生将获得关键经验，学习如何应用理论，并弥合理论和现实世界测试之间的差距。在这个项目中工作的研究生将针对代表不足的或少数群体。我们将通过大学现有的K-12推广计划、女性工程学计划、高中工程系统导论(HITES)和中学工程导论计划(MITE)，向当地公立学校和代表不足的社区的学校展示拟议的研究活动，以吸引感兴趣的高中生报读理工科课程。在这个项目中受雇的PI和学生将在这些活动中担任演讲者和导师。

1032523ZhangThe overall goal of this Broadening Participation Research Initiation Grants in Engineering (BRIGE) plan is to create novel microwave and laser diagnostic techniques for quantitative intermediate species measurements in fossil fuel and biofuel combustions at atmospheric and higher pressures and to educate students on the fundamental laser physics, combustion science and energy-related technologies. Combustion of fossil fuels currently provides about 85% of the energy consumed worldwide and generates the majority of the airborne pollutants. Biofuel is an alternative renewable energy source and its combustion reduces emission of some pollutants. In principle, combustion of all fuels proceeds through a multitude of elementary reaction steps. Atomic, molecular radical and complex molecular species play dominant roles in controlling the networks of chemical processes, many of which are not well understood by existing diagnostic techniques since most of those species are transient and at low concentrations. In particular, biofuel combustion is poorly understood due to the enormously complicated chemical processes, which challenge the limitations of diagnostic tools and make numerical simulations exceptionally difficult. Systematic study of the intermediate chemical compounds and their reactions in fossil fuel and biofuel combustions using novel diagnostic techniques may result in revolutionary development of more energy efficient and environmentally friendly devices and facilities, contributing to the solution of economical and societal issues such as global climate change.Intellectual Merit In this research novel microwave and laser diagnostic techniques, resonant coherent microwave scattering from localized Resonance-Enhanced Multi-Photon Ionization (REMPI) and photoionization of molecules at Rydberg states will be used to identify intermediate trace species with a sensitivity at ~100 ppb (parts per billion) level in and around the flame zone in combustions at atmospheric and higher pressures. Species to be followed include H and O atoms, CH3 and HCO radicals, and complex isomer-resolved molecules C6H6 and C7H8 etc. The techniques use one or two frequencytunable lasers to selectively generate ionization of a specific specie and resonant coherent microwave scattering to quantitatively detect the evolution of species concentration through the electrons inside the ionization region. These features combine to offer a high-precision, quenching-robust ionization spectroscopy, which can quantitatively and in-situ measure concentrations of the species at pressures up to and including operating combustor pressures. The application of the novel diagnostic techniques in measuring the intermediate species will greatly advance our understanding of fundamental combustion phenomena. A systematic diagnostic evaluation of biofuel combustions under well-characterized conditions will provide fundamental species information that can be used to validate and calibrate existing chemical kinetic models of biofuel combustions, possibly leading to improved combustion efficiency and more versatile and less polluting biofuel sources and devices.Broader Impact The proposed research will develop a new capability that may have broad impacts on many fields of engineering such as aerospace, mechanical, transportation and other industries that rely on the combustion. The planned research is complemented by a detailed educational plan that will have broad impacts on teaching the next generation of the workforce and the outreach efforts that will have a positive influence toward broad community education. As a part of the proposed educational efforts, the PI will develop two courses directly based on the research. The laboratory work will be designed for the courses to facilitate a more open-ended approach to engineering education upon which the students will gain critical experience in learning how to apply theory and bridge gaps between theory and real-world tests. Graduate students working in this project will target the underrepresented or minority groups. We will expose the proposed research activities to both local public schools and schools from underrepresented communities through the university's existing K-12 outreach program, Women in Engineering Program, the High School Introduction to Engineering System (HITES) and the Middle School Introduction to Engineering Program (MITE) to attract interested high school students to enroll in science and engineering programs. The PI and students employed in this project will be speakers and mentors at these events.