Laser piloted ignition of electrical wire in microgravity
Laser piloted ignition of electrical wire in microgravity
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DOI：
10.1016/j.proci.2018.06.089
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发表时间：
2019-01-01
影响因子：
3.4
通讯作者：
Fernandez-Pelloe, Carlos
中科院分区：
文献类型：
--
作者：
Kobayashi, Yoshinari;Konno, Yusuke;Fernandez-Pelloe, Carlos
本文研究了在正常重力和微重力条件下，利用激光诱导火花点火导线的实验。在微重力抛物线飞行中，利用实验室金属丝，在氧浓度为14-21%和外部辐射高达15.9千瓦/米（2）的条件下进行了独特的实验。导线样品由2.5 mm厚的芯线（使用实心铜（Cu）或空心不锈钢（SS）管）和0.75 mm厚的黑色聚乙烯（PE）绝缘层组成。这是首次在微重力条件下以激光诱导火花为先导的固体燃料点火实验。实验结果表明，无论氧气水平如何，微重力下的点火延迟时间总是小于正常重力下的点火延迟时间，表明微重力空间环境中的火灾风险较高。随着热通量和氧浓度的增加，观察到自燃。而且，如果堆芯暴露在外部热源下，它可以加热绝缘层以促进点火，这与过去点火研究中发现的热沉不同。这项独特的研究提供了有关微重力和未来长期太空旅行中电线火灾风险的宝贵信息。(C)2018燃烧研究所爱思唯尔公司出版All rights reserved.
This work studied the piloted ignition of electrical wires in both normal gravity and microgravity using the laser-induced spark. Unique experiments were conducted in the microgravity parabolic flight with laboratory wires under the oxygen concentration of 14-21% and external radiation of up to 15.9 kW/m(2). The wire sample consists of a 2.5-mm thick core, using the solid copper (Cu) or the hollow stainless steel (SS) tub; and a 0.75-mm thick black polyethylene (PE) insulation. This is the first piloted-ignition experiment on solid fuel in microgravity with the laser-induced spark as the pilot. Experimental results show that regardless of the oxygen level, the ignition delay time is always smaller in microgravity than in normal gravity, indicating a higher fire risk in the microgravity space environment. As the heat flux and the oxygen concentration increase, auto-ignition is observed. Moreover, if the core is exposed to the external heating source, it can heat the insulation to promote the ignition, different from the heat sink found in past ignition research. This unique research provides valuable information about the fire risk of electrical wire in microgravity and future long-term space travel. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.