Flame spread over electric wire in sub-atmospheric pressure

Nakamura, Yuji; Yoshimura, Nobuko; Ito, Hiroyuki; Azumaya, Keisuke; Fujita, Osamu

doi:10.1016/j.proci.2008.06.146

Cited by 121 publications

(59 citation statements)

References 15 publications

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“…This study follows the aforementioned studies by Fujita and coworkers [5][6][7][8][9][10]12] and focuses on the cable to cable interactions. While the main objective of understanding the influence of cable to cable interactions on flame spread rates remains, the present paper documents a new experimental rig that has been custom-designed to conduct experiments in parabolic flights.…”

Section: Introductionmentioning

confidence: 91%

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Fire safety in space – Investigating flame spread interaction over wires

et al. 2016

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In order to reduce the uncertainty and risk in the design of spacecraft fire safety systems, a new experimental rig that allows the study of concomitant flames spreading over the coating of parallel cylindrical wires in an air flow parallel to the wires in microgravity has been developed. The parabolic flight experiments were conducted at small length-and timescales, i.e. typically over 10 cm long samples for up to 20 seconds. For the first time, the influence of neighboring spread on the mass burning rate was assessed in microgravity. The observations are contrasted with the influence characterized in normal gravity. The experimental results are expected to deliver meaningful guidelines for future, planned experiments at a larger scale.Arising from the current results, the issue of the potential interaction among spreading flames also needs to be carefully investigated as this interaction plays a major role in realistic fire scenarios, and therefore on the design of the strategies that would allow the control of such a fire. Once buoyancy has been removed, the characteristic length and time scales of the different modes of heat and mass transfer are modified. For this reason, interaction among spreading flames may be revealed in microgravity, while it would not at normal gravity, or vice versa. Furthermore, the interaction may lead to an enhanced spread rate when mutual preheating dominates or, conversely, a reduced spread rate when oxidizer flow vitiation is predominant.In more general terms, the current study supports both the SAFFIRE and the FLARE projects, which are large projects with international scientific teams. First, material samples will be tested in a series of flight experiments (SAFFIRE 1-3) conducted in Cygnus vehicles after they have undocked from the ISS. These experiments will allow the study of ignition and possible flame spread in real spacecraft conditions, i.e. over real length scale samples within real time scales. Second, concomitant research conducted within the FLARE project is dedicated to the assessment of new standard tests for materials that a spacecraft can be composed of. Finally, these tests aim to define the ambient conditions that will mitigate and potentially prohibit the flame spread in microgravity over the material studied.

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Section: Introductionmentioning

confidence: 91%

“…Thus, some governing processes have been identified [10], and it has been found that the "wire-driven mode" controls the spread rate over the coating of a high conductivity metallic core (Fe), while the spread rate follows a "flame-driven mode" for a low conductivity metallic core (Ni/Cr).…”

Section: Introductionmentioning

confidence: 99%

Fire safety in space – Investigating flame spread interaction over wires

et al. 2016

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“…1. Experimental set-up (left) and a typical observation of flame spreading (right) over polyethylene (PE) coated electric wire (Nakamura et al, 2009) In the past, a few analytical methods offered an exact solution (Neumann, 1863). Even though they were mathematically robust, applicable ranges of solution are limited to onedimensional cases of an infinite or semi-infinite region with simple initial and boundary conditions and constant thermal properties.…”

Section: Wwwintechopencommentioning

confidence: 99%

“…Our ultimate goal is to understand each contribution properly and develop simplified model of wire combustion. To this date, the precise experimental observation of combustion behavior of electric wire has been performed by authors' group (Nakamura et al, 2008a(Nakamura et al, , 2008b(Nakamura et al, , 2009, as shown schematically in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

Kim¹,

Hossain²,

Kim³

et al. 2011

Two Phase Flow, Phase Change and Numerical Modeling

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“…Over the past few decades, a series of experimental studies on burning behavior of electric wire has been conducted, providing a rich experimental database [3][4][5][6]. In particular, Nakamura et al studied flame spread over electric wires insulated by polyethylene (PE) under sub-atmospheric pressure in normal gravity [7][8][9], and reported that molten PE significantly deformed and eventually dropped from the bulk of the insulation during the spreading event (see Fig. 3 in [8]).…”

Section: Introductionmentioning

confidence: 99%

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

Kim

Hossain

Nakamura

2013

International Journal of Heat and Mass Transfer

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Numerical simulations are performed in order to examine the time-dependent melting, and heavily deforming processes of phase change material (PCM) subjected to local heating. By comparing cases with and without deformation, the impact of the inclusion of a deformation model is firstly addressed to understand what influences the precise melting behavior. Mass, momentum and energy conservation equations are solved in a 2-D system based on a fixed grid by means of a finite volume method. The Volume of Fluid (VOF) method and the Enthalpy-Porosity method are applied to model the deformable liquid-gas interface and the melting processes, respectively. Results successfully show the melting, subsequent deformation and dropping-off behavior of the molten PCM. It is found that the inclusion of the deformation model enhances the melting owing to the increase of the total received heat; namely, widening of the contact area at the melting front and induced flow motion inside molten PCM improve the heat transfer toward the melting front. Parametric studies by varying the applied Stefan number so as to change the surface tension are also made to ensure the above-mentioned enhancement mechanism is universally applicable.

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Flame spread over electric wire in sub-atmospheric pressure

Cited by 121 publications

References 15 publications

Fire safety in space – Investigating flame spread interaction over wires

Fire safety in space – Investigating flame spread interaction over wires

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

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