Tech Briefs

A collection of reports presents a detailed description of a research program that focused on fundamental investigations of mixing and combustion in turbulent subsonic and supersonic flows like those encountered in high-speed air-breathing aircraft engines. The research included close coordination of effort between experiments and numerical simulations. Recent advances in instrumentation, including some made as part of this program, were utilized in the experiments. The research has been responsible for significant progress in the understanding of molecular mixing in high-speed flows in complicated geometries relevant to scramjet combustors and to high-speed aircraft engines in general. The research included a study oriented toward improving predictions of hydrocarbon flames in such flows and understanding the requirements for combustion of hydrocarbons and holding flames. The study involved comparisons of detailed experiments and detailed predictions of phenomena in stagnation-flame environments that replicate the fundamental effects that influence the stability and extinction of flames. An investigation of the three-dimensional structure of scalar dispersion, with a focus on grid turbulence, has been started and already has yielded new information with relevance to applications of turbulent mixing, including non-premixed combustion and dispersion of pollutants.

This work was done by Paul Dimotakis, Laurent Benezech, Jeffrey Bergthorson, Aristides Bonanos, Earl Dahl, Michael Johnson, Garrett Katzenstein, Daniel Lang, George Matheou, Christina Mojahedi, Carlos Pantano, Kazuo Sone, Bahram Valiferdowsi, D. G. Goodwin, S. Lombeyda, and D. I. Meiron of California Institute of Technology; and J. W. Shan of Rutgers University for the Air Force Research Laboratory.

AFRL-0045

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Mixing and Combustion in Turbulent, High-Speed Flows (reference AFRL-0045) is currently available for download from the TSP library.

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