Flame Front Geometry and Stretch During Interactions of Premixed Flames with Vortices

Abstract

Abstract Flame front geometry and flame stretch during interactions of premixed flames with vortices at various configurations are computationally investigated using a kinematical relationship between vortex-induced velocity and flame propagation velocity, in conjunction with Lagrangian coordinates to represent the flame front. The maximum flame stretch that can occur during an interaction with a single vortex is found to be very close to Uθ/rm + SL/2rm, while the mean flame stretch has a maximum that asymptotes to 18-23% of this value for vortex radii between 1.25 and 5.0 mm as UθSL is increased to 2. For flames interacting with a counter-rotating vortex pair, the flame stretch near the flow symmetry axis increases when the spacing between the vortices increase to align the velocity vectors with the flame front; while the flame stretch away from this region is relatively independent of the action of the opposite vortex and is determined primarily by the vortex velocity and length scale similar to the sin...