Modeling of Flammability Limits of Thin Materials in Microgravity Environment

Int. J. Microgravity Sci. Appl. 2014p179
Author
S. TAKAHASHI, K. TSUBOI, T. IHARA and S. BHATTACHARJEE
Organization
Department of Mechanical Engineering, Gifu University, Department of Mechanical Engineering, San Diego State University
Abstract
A model for flammability limits of thermally thin materials in microgravity environment has been developed by scale analysis. The flame spread over a thermally thin material with an opposed flow has two extinction limits; one is the blow-off limit and the other is radiation extinction. These limits are expressed by the following non-dimensional parameters, Da and Rrad as Da=1 and Rrad=1, respectively. In the previous model, the intersection of these limits corresponded to the minimum limiting oxygen concentration (MLOC). However, near the MLOC condition, due to the coupling of the effects of radiation and kinetics, the MLOC was far underestimated than the measured MLOC. In the new model, non-dimensional equation is proposed to take account of the coupling effect. The predicted extinction limit with the new model agrees with the actual limit obtained by flight experiments.
Keyword(s)
Flame spread, Flammability map, Scale modeling, Extinction, Damköhler number
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