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Cool flames at terrestrial, partial, and near-zero gravity
Please use this identifier to cite or link to this item:
http://hdl.handle.net/1860/1878
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| Title: | Cool flames at terrestrial, partial, and near-zero gravity |
| Authors: | Foster, Michael Robert
Pearlman, Howard |
| Keywords: | Cool flame
Low-temperature reaction
Natural Convection
Autoignition
Partial gravity |
| Issue Date: | Oct-2006 |
| Publisher: | Elsevier Inc. |
| Citation: | M. Foster and H. Pearlman (2006) Cool flames at terrestrial, partial, and near-zero gravity, Combust. Flame, 147 (1-2), 108-117. |
| Abstract: | Natural convection plays an important role in all terrestrial, Lunar, and Martian-based, unstirred, static reactor
cool flame and low-temperature autoignitions, since the Rayleigh number (Ra) associated with the self-heating of
the reaction exceeds the critical Ra (approximately 600) for onset of convection. At near-zero gravity, Ra < 600
can be achieved and the effects of convection suppressed. To systematically vary the Ra without varying the mixture
stoichiometry, reactor pressure, or vessel size, cool flames are studied experimentally in a closed, unstirred,
static reactor subject to different gravitational accelerations (terrestrial, 1g; Martian, 0.38g; Lunar, 0.16g; and reduced
gravity, ∼10^−2g). Representative results show the evolution of the visible light emission using an equimolar
n-butane:oxygen premixture at temperatures ranging from 320 to 350°C (593–623 K) at subatmospheric pressures.
For representative reduced-gravity, spherically propagating cool flames, the flame radius based on the peak
light intensity is plotted as a function of time and the flame radius (and speed) is calculated from a polynomial
fit to data. A skeletal chemical kinetic Gray-Yang model developed previously for a one-dimensional, reactive–
diffusive system by Fairlie and co-workers is extended to a two-dimensional axisymmetric, spherical geometry.
The coupled species, energy, and momentum equations are solved numerically and the spatio-temporal variations
in the temperature profiles are presented. A qualitative comparison is made with the experimental results. |
| URI: | http://hdl.handle.net/1860/1878 |
| Appears in Collections: | IST Sandbox
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