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Finite-Rate Diffusion-Controlled Reaction in a Vortex.

Finite-Rate Diffusion-Controlled Reaction in a Vortex.
(1156 K)

Rehm, R. G.; Baum, H. R.; Tang, H. C.; Lozier, D. C.

Combustion Science and Technology, Vol. 91, No. 1-3,
143-161, 1993.

### Keywords:

flame fronts; formulations; equations; diffusion flames;
bimolecular reactions

### Abstract:

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The influence of a vortex on a gaseous diffusion
reaction is examined. The vortex is taken to be two
dimensional, and the species are initially assumed to
occupy adjacent half spaces. In the flame-sheet limit,
thermal expansion and the effects of variable diffusion
are taken into account. A global similarity solution
exists for this problem, and a simple expression for the
solution is determined in the asymptotic limit of large
Schmidt number. The problem is also analyzed for
finite-rate chemistry, appropriate for an isothermal,
bimolecular reaction. The problem depends upon three
parameters, Reynolds number, Schmidt number and the
equivalence ratio, with the Damkohler number equal to
the dimensionless time. The structure of the reaction
region normal to the flame front is examined as a
function of time. The evolution of the reaction to a
state relation, dependent only upon the mixture-fraction
variable, is demonstrated as the Damkohler number
becomes large.
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