The stability of weakly stretched flames

Abstract

In this study, the stability of plane stretched flames, more specifically plane flames in straining fields, has been examined. It is shown that flame stretch stabilizes long wavelength disturbances and so can suppress, in this regime the hydrodynamic instability. If in addition, the mixture is deficient in the reactant which is also the weakly diffusing component, and hence the Lewis number is greater than unity, thermal effects will stabilize the short wavelength disturbances. Thus sufficiently strong stretch can render a flame absolutely stable. The instability, which first appears by reducing the strain rate from the critical value, is in the form of longitudinal cells with ridges in the direction of stretch. By reducing the strain rate further a cellular structure will probably emerge.