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Candle Flames in Non-Buoyant AtmospheresThis paper addresses the behavior of a candle flame in a long-duration, quiescent microgravity environment both on the space Shuttle and the Mir Orbiting Station (OS). On the Shuttle, the flames became dim blue after an initial transient where there was significant yellow (presumably soot) in the flame. The flame lifetimes were typically less than 60 seconds. The safety-mandated candlebox that contained the candle flame inhibited oxygen transport to the flame and thus limited the flame lifetime. 'Me flames on the Mir OS were similar, except that the yellow luminosity persisted longer into the flame lifetime because of a higher initial oxygen concentration. The Mir flames burned for as long as 45 minutes. The difference in the flame lifetime between the Shuttle and Mir flames was primarily the redesigned candlebox that did not inhibit oxygen transport to the flame. In both environments, the flame intensity and the height-to-width ratio gradually decreased as the ambient oxygen content in the sealed chamber slowly decreased. Both sets of experiments showed spontaneous, axisymmetric flame oscillations just prior to extinction. The paper also presents a numerical model of candle flame. The model is detailed in the gas-phase, but uses a simplified liquid/wick phase. 'Me model predicts a steady flame with a shape and size quantitatively similar to the Shuttle and Mir flames. ne model also predicts pre-extinction flame oscillations if the decrease in ambient oxygen is small enough.
Document ID
20000005087
Document Type
Reprint (Version printed in journal)
Authors
Dietrich, D. L. (NASA Lewis Research Center Cleveland, OH United States)
Ross, H. D. (NASA Lewis Research Center Cleveland, OH United States)
Shu, Y. (Case Western Reserve Univ. Cleveland, OH United States)
Tien, J. S. (Case Western Reserve Univ. Cleveland, OH United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1999
Subject Category
Inorganic, Organic and Physical Chemistry
Funding Number(s)
PROJECT: RTOP 963-15-OG
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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