PROPAGATION, STRUCTURE, AND LIMIT PHENOMENA OF LAMINAR FLAMES AT ELEVATED PRESSURES

ABSTRACT

Recognizing the importance of pressure on the intrinsically nonlinear behavior of chain mechanisms in fuel oxidation, and its role in the proper interpretation of the diffusive and convective transport in variable density flows, effects of elevated pressure on various combustion phenomena associated with laminar flames are discussed. Specific topics covered include the falloff behavior and explosion limits in chemical kinetics; the chain-affected complex and sometimes nonmonotonic response of the laminar burning flux, the overall reaction order and activation energy, the flammability and extinction limits, the cellular and pulsating flamefront instabilities; and the importance of density and hence pressure weighting in the interpretation of laminar burning fluxes, laminar flame thicknesses, and flow straining.

Keywords:

• flame kinetics
• hydrogen kinetics
• laminar flame propagation
• high-pressure flames
• density weighting
• supercritical flames

This review was prepared under the sponsorship of the Air Force Office of Scientific Research and NASA, with the technical monitoring of Drs. Julian M. Tishkoff and Merrill K. King, respectively. The assistance of Dr. Tianfeng Lu and Mr. Grunde Jomaas in the preparation of this manuscript is very much appreciated.