The interaction of flame curvature and stretch, part 1: The concave premixed flame

Abstract

Premixed flames with radii of curvature on the order of the preheat zone thickness are studied with activation energy asymptotics. The changes in flame speed caused by varying the flame stretch as the flame radius is held fixed are calculated. The result of this calculation is that the decrease in flame speed due to flame stretch is amplified by more highly curved flames. When there is no flame stretch, the flame speed is independent of the flame radius, and so flame curvature in and of itself does not alter flame speed, but is important in determining the changes in flame speed when stretch is present.