CAREER: Reactive Fluid Mechanics of Mesoscale Hydrocarbon-based Power Generation

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

CAREER: Reactive fluid mechanics of mesoscale hydrocarbon-based power generation PI: Dimitrios C. Kyritsis, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign Abstract Miniaturization to impressively small dimensional scales has already been demonstrated in information storage, electronics, manufacturing, and recently, micro-electro-mechanical systems (MEMS). However, development of equivalent small-scale power sources seems to be lagging in this quest for systems miniaturization. Currently available, grid-independent power sources are predominantly chemical batteries, which are devices of notoriously limited power density. Exploiting the high power density of hydrocarbons in "liquid fuel batteries" could increase drastically the autonomy of portable power sources and provide a substantial degree of independence of human activity from centralized grids. In order for this to be achieved, the fundamentals of the related reactive fluid mechanics have to be known. This research is a comprehensive experimental and theoretical investigation of the regime of reactive fluid mechanics that is relevant for mesoscale, hydrocarbon-based power generation. Using a combination of gaseous phase and surface experimental techniques, we investigate the flow elements that will be the "building blocks" of mesoscale burners, such as the flat plate boundary layer, the flow around a cylinder, as well as the flow around arrays of cylindrical and flat elements and through mesoscale channels. These flows are studied in the regime of intermediate Reynolds, Peclet, and Damkhler numbers that is relevant for small-scale power generation and where several usual approximations are not valid. A particular emphasis is placed on flows over catalytically coated surfaces, since the relatively small combustion temperatures desired in battery-size applications make catalysis a necessary prerequisite for stability. Laser Induced Fluorescence measurements and Gas Chromatography-Mass Spectrometry analysis of the gaseous phase are combined with infrared thermography and Fourier Transform Infrared measurements on the surface to provide data regarding fuel depletion, reactive zone structure, and exhaust gas temperature and composition as a function of surface temperature and species adsorption/desorption. Based on these results, a refinement of early theoretical analyses of these flows, which relied on uniform surface temperature and infinite rates of surface reactions, is pursued. In concert with the research component, modern challenges in thermal science are the theme of parallel educational and outreach activities. A senior/graduate level course in laser diagnostics was introduced to the University curriculum. A digital photography competition under the title "Flames" is regularly organized among K-12 students of Eastern Central Illinois to investigate naturally occurring and/or laboratory flames. Autonomous power generation will be introduced to the continuing education program of AIAA through a short course the PI will develop based on his results. Enhancement of interest in engineering and participation of minorities and underrepresented groups is pursued through outreach activities and graduate student recruitment for the project.