A theoretical analysis is presented to study the extinction characteristics of a diffusion flame near the leading edge of a thin fuel plate in slow, forced convective flows in a microgravity environment. The mathematical model includes two-dimensional Navier-Stokes momentum, energy and species equations with one-step overall chemical reaction using second-order finite rate Arrhenius kinetics. Radiant heat loss on the fuel plate is applied in the model as it is the dominant mechanism for flame extinguishment in the small convective flow regime. A parametric study based on the variation of convective flow velocity, which varies the Damkohler number (Da), and the surface radiant heat loss parameter (S) simultaneously, is given. An extinction limit is found in the regime of slow convective flow when the rate of radiant heat loss from fuel surface outweighs the rate of heat generation due to combustion. The transition from existent envelope flame to extinguishment consists of gradual flame contraction in the opposed flow direction together with flame to extinguishment consists of gradual flame contraction in the opposed flow direction together with flame temperature reduction as the convective flow velocity decreases continuously until the extinction limit is reached. A case of flame structure subjected to surface radiant heatloss is also presented and discussed.
Diffusion flame extinction in slow convective flow under microgravity environment
Loeschen einer Diffusionsflamme in einer langsamen konvektiven Stroemung unter Einfluss der Mikrogravitaet
Symp. on Microgravity Fluid Mechanics, the Winter Annual Meeting of the ASME ; FED-42 , Dez ; 13-23
1986
11 Seiten, 8 Bilder, 2 Tabellen, 13 Quellen
Conference paper
English
Extinction Characteristics of Cup-Burner Flame in Microgravity
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