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MAE Seminar: “Local Extinction and Edge Flames under Gas Turbine Engine Conditions”
February 11 @ 10:00 am - 11:00 am
In gas turbine engine augmentors, flames are stabilized in high speed flows using bluff body flame holders. The limiting conditions for flame stability are impacted by the formation of holes in the reacting flame sheet due to interactions with the turbulent flow. In this seminar, a range of optical diagnostics are shown for understanding flame hole formation and the resulting flame edge propagation behavior both in augmentors and in simplified combustors designed to understand details of flame holes and edge flames. High-speed chemiluminescence imaging, planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) are used in the augmentor to identify conditions under which flame holes lead to destabilization of the augmentor flame. An improved model for predicting flame blowoff was developed that relies on a single extinction scalar dissipation rate for defining the formation of flame holes, which is studied in greater detail in a separate series of measurements and numerical simulations on a laminar counterflow flame, using PIV, PLIF, Rayleigh- and Raman-scattering spectroscopy. The results show that extinction limits from the literature do not capture the impact of heat flux through the edge that is required to correctly predict extinction scalar dissipation rates.
Dr. Michael Renfro is the Tennessee Valley Authority Professor and Chair of the Department of Mechanical Engineering at the University of Kentucky. Prior to joining Kentucky in 2015, he was on the faculty at the University of Connecticut where he also served as Associate Department Head from 2009-2014 and as the Director of Graduate Studies from 2006-2009. He received his Ph.D. from Purdue University in 2000. Dr. Renfro’s research is in the area of optical diagnostics applied to power production technology, particularly combustion, gas turbine and fuel cell systems. Current research focuses on the development and use of laser-based measurement tools to study flame stability and propagation; ignition and extinction; sensor development for high temperature fluid systems; and non-destructive optical evaluation of high-temperature coatings. He has advised 9 doctoral and 16 master’s thesis students, and has supervised over 40 undergraduate researchers. Dr. Renfro’s research has been supported by NSF, AFOSR, ARO, DOE, NASA, and industry with total funding over $16M. He received an NSF CAREER award in 2002. Dr. Renfro has published over 65 journal and 110 conference papers. Professor Renfro teaches undergraduate and graduate courses in thermodynamics and fluid mechanics and has received multiple department and university awards for teaching.