Diffusion Flame Stabilization by a Recirculating Flow — Flame Spread Downstream of an Ignition Point
The concept of well-stirred reactors is often employed to discuss flame stabilization by a recirculating flow. Such a treatment is incapable of predicting the properties of the free shear layer outside of the wake, which are important in view of the combustion in the reattached shear layer. In the present analysis an approximation for the flow outside of the wake is proposed which allows one to compute the temperature and concentration fields in the free shear layer. Using Linan’s diffusion flame asymptotics, a parabolic free boundary problem for the flame is derived. It is shown that physically relevant solutions for this problem exist only up to a limited value of the entrance velocity U O. This velocity defines a blow-off velocity for the flame.
KeywordsShear Layer Flame Spread Recirculate Flow Flame Stabilization Free Shear Layer
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