简介: |
The understanding of the combustion characteristics of practical fuels is essential for the improvement of air-breathing combustors. This understanding will guide the formulation of reliable surrogate fuels that mimic the behavior of the real fuels and the development of the attendant detailed chemical kinetic mechanisms. In this talk, some of our recent contributions towards the understanding of the combustion characteristics of practical fuels, proposed surrogate mixtures, and surrogate-related neat compounds will be presented. More specifically, the effects of fuel variability, fuel chemical class distribution, and molecular transport will be discussed. Experimentally determined ignition and extinction limits of multiple batches of gasoline and jet fuel demonstrate the significant variation of limit phenomena of practical fuels. Comparison between experimental data obtained for neat hydrocarbon compounds, a wide range of jet fuels, and jet fuel surrogates demonstrate a hierarchy of chemical classifications on limit flame phenomena. The experiments involving neat compounds were modeled through the use of detailed description of molecular transport and recently developed chemical kinetics. Through the use of rigorous sensitivity, reaction path, and flame structure analyses, the relative effects of diffusion and chemical kinetics were quantified and understood. More specifically, for large hydrocarbon molecules and under certain conditions, the effect of diffusion on fundamental flame properties was found to be of the same order or higher with that of kinetics. The significance of this finding is further amplified by the limited knowledge of diffusion coefficients of long linear fuel molecules. Finally, it was determined that for certain liquid fuels, detailed mechanisms that predict laminar flame speeds fail to predict satisfactorily extinction limits. These findings need to be considered in efforts towards the development of surrogates of practical fuels so that combustors are modeled with increased degree of confidence.
BIOGRAPHICAL DATA of Fokion N. Egolfopoulos
Fokion N. Egolfopoulos received a Diploma in Mechanical Engineering from the National Technical University of Athens in February 1981 and a M.Sc. in Mechanical Engineering from San Jose State University in December 1984; from March 1981 to May 1983 he served military service (compulsory) in the Greek Navy. Subsequently, he received his Ph.D. in Mechanical Engineering from University of California at Davis in June 1990, after having spent the last two years of his doctoral research at Princeton University. After his formal education he has been associated with the Combustion and Fuels Laboratory at Princeton University as a Research Associate from June 1990 to August 1991.
In August 1991 he joined the Department of Mechanical Engineering at the University of Southern California at the rank of Assistant Professor. In April 1997 he was promoted to the rank of Associate Professor and subsequently in June of 2002 to the rank of Full Professor. From January 1998 until November of 2001 he was also appointed as Visiting Associate and Lecturer of the Department of Aeronautics at the California Institute of Technology.
Professor Egolfopoulos' current research interests include: combustion and propulsion, microgravity combustion, alternative and renewable fuels, pollutant formation and destruction, and hypersonic combustion. His work is and has been supported by Air-Force Office of Scientific Research, NASA, Department of Energy, National Science Foundation, the California Energy Commission, PSA Peugeot-Citröen, the Southern California Gas Company, TRW, and the California Institute for Energy Efficiency. He has authored and co-authored sixty six (66) archival journal publications, two (2) book chapters, one hundred and five (105) conference proceedings and reports, and has given ninety three (93) scholarly presentations.
He was a recipient of the Silver Medal of the Combustion Institute at the Twenty-Second International Combustion Symposium. During his tenure at USC he has received several teaching and research awards.
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