Effect of Sample Width on Flame Spread Rate over a Thin Material in Microgravity

Abstract

The effect of the sample width on the flame spread rate over a thin PMMA film in microgravity has been investigated by experiments and scale analysis. The oxygen level of the ambient gas is kept fixed at 30% while different diluents-N2, Ar, He, and CO2-are used. The sample width is also used as a parameter, varying through 5mm, 10mm, and 20mm. When helium is used as the diluent, the conductive heat loss to the sides becomes large, and therefore, the flame is suppressed with a significant drop in the flame spread rate and flame size, especially at low oxygen level and for narrow sample widths. For other diluents, the radiative loss is the dominant factor for the suppression, and the sample width has small impact. These experimental findings can be explained with the scale analysis.

Flame spread behaviour of Polydimethylsiloxane (PDMS) membranes in 1 g and µg environments

“…The data from Takahashi et al [31][32][33], only one point coincides with the current data. In the experimental work conducted by Takahashi et al [31][32][33], the sample width tested was either 10 mm or 20 mm.…”

“…The data from Takahashi et al [31][32][33], only one point coincides with the current data. In the experimental work conducted by Takahashi et al [31][32][33], the sample width tested was either 10 mm or 20 mm. As a consequence, their flame spread was three-dimensional in nature and was affected either by side oxygen supply or cooling (threedimensional effect) [34].…”

“…Figure 4 -Theoretical and experimental flame spread velocities for the 0.125 mm thick PMMA sample as a function of the opposed forced flow velocities. The data is from the current study and from Takahashi et al (2009) [31] , Takahashi et al (2012)[32], andTakahashi et al (2007) [33].…”

Behavior of Flame Spread on Thin PMMA near Extinction Limit at Low Oxygen Level

“…5. This result is caused by three-dimensional effect due to large thermal diffusivity of helium 11) . In our previous research, the non-dimensional heat transfer toward side direction, R side , was expressed as Eq.…”

A historical overview of experimental solid combustion research in microgravity

“…Consequently, other diagnostic systems to measure or qualitatively analyse the temperature and temperature changes in the gas-phase and solid-phase have been used. These methods are holographic interferometry [17,[80][81][82][83][84], rainbow Schlieren [23] and infrared cameras (IR) [27,29,35,80,[85][86][87][88]. For IR cameras, a bandwidth from 3.8 to 4.28 µm to filter the radiation from the gas-phase is required to provide the solid-phase temperatures.…”