Extinction of a diffusion flame in supersonic mixing layer

Abstract

Because of the need for propulsion devices designed to provide chemical reactions and heat release in high-speed streams, there has recently been renewed interest in supersonic shear layers. The asymptotic studies of combustion at low Mach numbers based on the one-step reaction model have significantly enhanced the understanding of ignition and flames. At high Mach numbers, an additional consideration is the viscous heating and its interaction with chemical reaction. Based on the one-step model, a semianalytical and numerical investigation of the viscous heating on ignition in a mixing layer was obtained by Jackson and Hussaini. More recently, the ignition problems in the supersonic mixing layer were asymptotically analyzed. All these analyses showed that viscous heating has a significant influence on the ignition. From these conclusions, another question is directive, that is, how and to what extent the viscous heating affects the flame structure and extinction. The objective of the present study is to show analytically this effect in a supersonic reactive mixing layer, in which two parallel streams with different velocities begin to mix and react downstream of a trailing edge of a splitting plate.