| 薛岩,方俊,王静舞.低压下聚乙烯绝缘层导线火蔓延熔融滴落实验分析[J].火灾科学,2017,26(4):191-197. |
| 低压下聚乙烯绝缘层导线火蔓延熔融滴落实验分析 |
| Experimental study on polyethylene insulation wire dripping phenomenon under sub-atmospheric pressure |
| 投稿时间：2017-02-17 修订日期：2017-04-10 |
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| DOI：10.3969/j.issn.1004-5309.2017.04.01 |
| 基金项目:国家自然科学基金资助项目（51636008，51576186，51323010）；国家重点研发计划项目（2016YFC0801504)；中央高校基本科研业务费项目（WK2320000036） |
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| 中文关键词: PE导线火蔓延 低压 氧浓度 熔融滴落极限 |
| 英文关键词:PE wire flame spread Sub-atmospheric pressure Oxygen concentration Dripping limits |
| 摘要点击次数: 144 |
| 全文下载次数: 885 |
| 中文摘要: |
| 低压导线火蔓延的研究对于飞机和航天器的防火安全具有重要意义。针对镍铬合金线芯、聚乙烯（PE）绝缘层导线火蔓延过程中的熔融滴落现象，在低压舱内开展了不同气压、不同氧气浓度的大量实验研究，获得了导线熔融滴落频率、质量和火蔓延速度，以及不同氧浓度熔融滴落的上下限。结果表明：（1）在熔融滴落过程中，由于滴落会产生向上的动量，从而使火焰在滴落后发生突然的“跳动”现象，火焰高度先增加后降低；（2）滴落上限和滴落下限随着氧浓度的增加而降低，并且可以划分为3个不同的区域：火蔓延仅存区；滴落和火蔓延共存区；无滴落无火蔓延区。滴落上限和滴落下限下降曲线在50%氧浓度、5 kPa压力发生会合，此后只有火蔓延而不存在滴落现象。（3）当压力降低时，由于线芯温度增加，线芯传导热量增加，导致绝缘层熔融速率加快，从而使得滴落频率增加，同时液滴的表面张力随着压力的降低而增加，使得低压下液滴的质量变大。 |
| 英文摘要: |
| This work reveals a detailed description of the dripping phenomenon during the wire flame spread process. Using NiCr core and Polyethylene insulation wire as the sample, we carried out experiments to measure the dripping frequency, droplet mass, flame spread rate as well as the dripping upper and lower limits. The results show that there is a “bouncing” phenomenon during the dripping process, and as the pressure decreases, the dripping frequency and droplet mass will increase owing to the increase of burning rate and surface tension. The flame spread rate is more sensitive to oxygen concentration than to pressure. The dripping upper and lower limits will decrease as the oxygen concentration increases. There are three regions of spreading, spreading and dripping, no spreading and dripping between the dripping upper and lower limits. These two limits will converge at 50% oxygen concentration and 5kPa, beyond that, there is no dripping phenomenon. |
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