Flammability limit of thin flame retardant materials in microgravity environments

Takahashi, Shuhei; Borhan, Muhammad Arif Fahmi bin; Terashima, Kaoru; Hosogai, Aki; Kobayashi, Yoshinari

doi:10.1016/j.proci.2018.06.102

Cited by 31 publications

(10 citation statements)

References 16 publications

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“…A likely fire cause in spacecrafts is ignition and flame spread over the wire insulation that is used in the numerous electric devices. Moreover, numerous studies showed that combustion phenomena in microgravity are different from normal gravity phenomena, especially due to the absence of buoyancy [2,3]. Therefore, it is important to understand the ignition and flame spread behavior on wire insulation in microgravity, especially in the environmental conditions associated with spacecraft.…”

Section: Introductionmentioning

confidence: 99%

Effect of ambient pressure on the extinction limit for opposed flame spread over an electrical wire in microgravity

Nagachi

Citerne

Dutilleul

et al. 2021

Proceedings of the Combustion Institute

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Section: Introductionmentioning

confidence: 99%

Effect of ambient pressure on the extinction limit for opposed flame spread over an electrical wire in microgravity

Nagachi

Citerne

Dutilleul

et al. 2021

Proceedings of the Combustion Institute

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“…Therefore, fire safety is an essential requirement for future manned space missions. To ensure the fire safety, numerous studies have been conducted on solid combustion in microgravity [2][3][4]. Also, many electrical devices and cables are installed in the spacecraft, and ignition of electrical wire is the most likely cause of fire accidents because of overloading or short circuiting [1].…”

Section: Introductionmentioning

confidence: 99%

Effect of Ignition Condition on the Extinction Limit for Opposed Flame Spread Over Electrical Wires in Microgravity

et al. 2019

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Flame spread over wire insulation plays a crucial role in spacecraft fire safety. To quantify the effect of the initial ignition condition on the Limiting Oxygen Concentration (LOC) of spreading flame over wire insulation, opposed flow flame spread experiments with wire insulation were conducted in microgravity (parabolic flights). Both ignition power (32.7 to 71.8 W) and heating time (5-15 s) were varied for an external flow of 100 mm/s. The sample wires were made of Polyethylene-coated Nickel-Chrome (NiCr) and Copper (Cu), respectively, both with inner core diameter of 0.50 mm and insulation thickness of 0.30 mm. A 0.50 mm diameter coiled Kanthal wire wrapped around the sample wire 6 times with 8 mm length was used as the igniter. The experimental results show that the LOC gradually decreases as the ignition power or heating time increases and eventually it reaches a constant value. Also, the effect of ignition condition on LOC was more pronounced for Cu wires than for NiCr wires. The variation range of LOC in the tested ignition condition in microgravity was larger than that of horizontal flame spread in normal gravity. This conclusion can have implication for future experiment in the International Space Station to avoid the wrong LOC value because of the insufficient initial ignition energy and will eventually lead to an improved fire safety in spacecrafts.

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“…3 corresponds to the MLOC, which is 14.8 %. In the previous experiment, 17) the minimum oxygen concentration in which the flame survived in microgravity environment was 14.7 % where the opposed flow velocity was 6cm/s. It is found that the prediction well agrees with the experimental result.…”

Section: The Limiting Curve Of Thin Pmmamentioning

confidence: 75%

Prediction of Limiting Oxygen Concentration of Thin Materials in Microgravity

Takahashi

Maruta

2018

AEROSPACE TECHNOLOGY JAPAN

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In order to predict the flammability limit of thin materials in microgravity environments without conducting microgravity experiments, we developed a simplified model for flame spread in an opposed flow by introducing two non-dimensional parameters which represent radiative quenching and blow-off extinction. Thin PMMA sheet and NOMEX HT90-40 fabric were used as the sample. For predicting the blow-off limiting curve, the pre-exponential factor and the activation energy are required, however, these properties are hardly available in the literature. Hence, we proposed a novel blow-off test in a forced flow to obtain empirical parameters which reproduce the actual blow-off phenomena correctly. Although the properties of NOMEX are unknown, the limiting curves of NOMEX with these empirical parameters well agreed with the results of the parabolic flights, and the obtained minimum oxygen concentration was also close to the experimental value.

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Flammability limit of thin flame retardant materials in microgravity environments

Cited by 31 publications

References 16 publications

Effect of ambient pressure on the extinction limit for opposed flame spread over an electrical wire in microgravity

Effect of ambient pressure on the extinction limit for opposed flame spread over an electrical wire in microgravity

Effect of Ignition Condition on the Extinction Limit for Opposed Flame Spread Over Electrical Wires in Microgravity

Prediction of Limiting Oxygen Concentration of Thin Materials in Microgravity

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