The 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.
