Downward flame spread and extinction over electric wires placed in a ground-based centrifuge

Konno, Yusuke; Ishikawa, Shoryu; Hashimoto, Nozomu; Fujita, Osamu

Downward flame spread and extinction over electric wires placed in a ground-based centrifuge

Konno, Yusuke; Ishikawa, Shoryu; Hashimoto, Nozomu et al.

Proceedings of The Combustion Institute, 2024, 40(1-4), 105199

Permalink : https://hdl.handle.net/2115/97238

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アクセス権	open access
URI	https://hdl.handle.net/2115/97238
タイトル	Downward flame spread and extinction over electric wires placed in a ground-based centrifuge
著者	Konno, Yusuke ; Ishikawa, Shoryu ; Hashimoto, Nozomu ; Fujita, Osamu
e-Rad_Researcher 10907728 著者名 Konno, Yusuke
著者名 Ishikawa, Shoryu
e-Rad_Researcher 70392751 著者名 Hashimoto, Nozomu
e-Rad_Researcher 10183930 著者名 Fujita, Osamu
言語	英語
キーワード	Flame spread
	Centrifuge
	Gravity effect
	Coriolis force
	Spacecraft fire safety
発行日	2024
出版者	Elsevier
収録物名	Proceedings of The Combustion Institute
巻(号)	40(1-4)
ページ	105199
抄録	This study investigates the downward flame spread over laboratory wire samples in a ground-based centrifuge. The specimens consist of low-density polyethylene (LDPE) insulation over metallic cores. Copper (Cu) and nickel- chrome (NiCr) were selected as core materials because they can establish different flame sizes under the same experimental conditions. The centrifugal force is varied from 0 G to 3 G by adjusting the rotational speed of the centrifuge. The flame shapes are photographed from two angles, revealing the tilt of the flame due to the Coriolis force as well as the centrifugal force. Flame spread rates and flame spread limits are also obtained as a function of centrifugal force with oxygen concentration and wire characteristics as experimental variables. As the centrifugal force increases, the flame spread rate decreases and the flammable range narrows. This suggests suppressed flammability under hyper-gravity conditions, explained by finite rate chemistry and thermal effects from flame shape deformation. The Cu sample with large thermal conductivity is strongly affected by the change in heat balance due to the change in flame shape, and the dependence of the flame spread rate and flame spread limit on the centrifugal force is pronounced. Additionally, the displacement of downstream flame is measured with respect to the wire position, and the ratio of Coriolis and centrifugal forces affecting the flame is estimated along with a simple analysis. The ratio of Coriolis force-to-centrifugal force on the flame is found to increase with decreasing the centrifugal force and the radius of rotation decreased.
資源タイプ	学術雑誌論文
出版タイプ	Accepted Manuscript
権利情報	Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
権利情報	© <2024>. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
PISSN	1540-7489
関連情報 (isVersionOf)	出版社版DOI https://doi.org/10.1016/j.proci.2024.105199