Effect of gas phase heat sink on suppression of downward flame spread over thin solid fuels

Effect of Gas Phase Heat Sink on Suppression of Opposed Flow Flame Spread over Thin Solid Fuels in Microgravity Environment

“…It is interesting to note that decrement in spread rates is steeper for the mesh with higher "N." Flame extinction was observed at certain minimum mesh distance from the fuel surface which ranged from 0.44 cm (for N = 5 cm −1 ) to 0.61 cm (for N = 40 cm −1 ). It should be pointed out here that in the preceding study [23] with downward spreading flame the minimum mesh distance for all mesh densities were between 0.15-0.17 cm. Thus while for normal gravity downward spreading flame the minimum distance was nearly independent of mesh density, here we see that extinction distances show a stronger dependency on wire mesh density "N." Further it is interesting to note that for N = 20 cm −1 and N = 40 cm −1 , the flame-spread rates at various mesh locations and the extinction distances (here at 0.60 cm to 0.61 cm, resp.)…”

“…The flame spreads in downward direction, and according to classical heat transfer theory on flame spread [22] over thin solid fuel, the opposed flow propagating flame spreads by heat feedback from the flame to the solid fuel upstream of the flame. The present model was extensively validated against experimental data in both microgravity environments [10] and in normal gravity (1g e ) [23], where a numerical study supported by experiments was carried out on flame inhibition by wire mesh of downward spreading flame. Thus, the present model is expected to offer reasonable prediction and physical insight into the flame suppression of microgravity-opposed flow spreading flame for experimental data which is not available in the literature.…”