A Multi-Scale Simulation Methodology for Turbulent Combustion Suresh Menon School of Aerospace Engineering Georgia Institute of Technology Currently, an area of focus of gas turbine engine design manufacturers is achieving stable lean combustion since pollutant emission (e.g., CO, NO, UHC, and soot) is minimized and fuel efficiency is increased. However, lean combustion systems are particularly sensitive to small perturbation in heat release that can result in flame extinction. Experiments also show that as the fuel-air mixture is made lean, CO emission first decreases and then suddenly increases rapidly as the lean flammability limit is reached. This rapid increase in CO is observed in all gas turbine engines (i.e., both premixed and spray systems), and is related to the onset of Lean Blowout (LBO) when the flame undergoes rapid instability, undergoes local quenching, and then globally extinguishes. LBO and/or flame oscillations are also observed in afterburners and in high pressure military combustor under certain conditions. Prediction of LBO and near-LBO physics requires not only resolution of the time-dependent flow-chemistry interactions but also inclusion of proper chemical kinetics. Furthermore, flame characteristics can change from flamelet-type to distributed reaction zone combustion as conditions close to LBO is reached. As a result, there is a need for a simulation strategy than can simulate a wide range of operational conditions with making any model adjustments. These requirements are equally relevant when considering advanced supersonic combustion ramjets (SCRAMJETS) where rapid fuel-air mixing, combustion and flame-holding all have to be properly predicted over a range of operating conditions. A multi-scale large-eddy simulation (LES) approach has been developed over the last few years that can be used for a wide range of operating conditions without any tunable parameters. A localized dynamic LES model for the subgrid kinetic energy is combined with a subgrid simulation of the scalar reaction-diffusion processes. Soot physics is also included in this formulation and relatively detailed kinetics is included using in-situ adaptive tabulation (ISAT) and/or artificial neural networks (ANN). Although computational cost is significant, efficient parallel implement allows application of this tool to full-scale premixed and liquid-fueled gas turbines, as well as to SCRAMJETS. Progress in application to various laboratory and operational devices will be discussed. Extension of this approach to simulate detonation in two-phase reactive mixtures will be briefly addressed as well. Brief Biography: Professor Suresh Menon is a Professor in the School of Aerospace Engineering at Georgia Tech. He completed B.Tech and M.Tech degrees in Aeronautical Engineering at Indian Institute of Technology, Kanpur in 1976 and 1978, respectively, and a Ph.D. in Aerospace Engineering from University of Maryland in 1984. Professor Menon joined Flow Industries, Kent, Washington, as a Research Scientist in 1984 and in 1988 became a Senior Scientist and Program Manager for the Computational Fluid Dynamics group in Quest Integrated, Inc. (formerly called Flow Research, Inc.). At Quest, Dr. Menon led research teams in various research projects such as the active control of combustion instability in ramjet engines, supersonic mixing studies, vertical takeoff and landing (VTOL) aircraft fluid dynamics, and hypersonic reentry dynamics. In 1992, he joined Georgia Institute of Technology as an Associate Professor and became a Professor in 1997. Professor Menon's area of expertise is in large-eddy simulation of turbulent reacting and non-reacting flows and he has developed unique simulation capabilities to study turbulent mixing in high Reynolds number flows, pollutant formation, ozone depletion in high-altitude aircraft jet plumes and combustion in gas turbine and ramjet/scramjet engines. He has been (and is currently) a principal investigator for a wide range of research projects funded by NASA, Air Force, Office of Naval Research, Army Research Office, DTRA, Department of Energy and National Science Foundation. He is also supported by many industries such as, General Electric Aircraft Engine Company, General Electric Power Systems, Pratt & Whitney, Rolls-Royce, Solar Turbine, BMW, Astrium Corporation and Ford Motor Company. He has published and/or presented over 350 papers. Professor Menon is an Associate Fellow of the AIAA, and a member of the American Physical Society, the American Society of Mechanical Engineers, the Combustion Institute and the Sigma Xi. He is a peer reviewer for numerous archival journals, NASA, NSF, DoD and DOE research proposals.