Abstract Flame propagation behavior over the polymer insulation of electrical wires can ignite adjacent combustibles and increase the scale of the fire. In this study, the flame propagation behavior over polyethylene (PE)-insulated wires was investigated theoretically and experimentally under varying pressures. The experiments were conducted in three cities with different altitudes (64, 76, and 100 kPa) and in a newly designed hypobaric chamber (7.5–101.3 kPa) for the first time. The flame morphology, structure, and spread rate were examined and discussed. The results show that pressure significantly affects flame propagation behavior. With increasing pressure, the flame illumination increases, and the flame shape changes, while the average flame height increases monotonously with decreasing average flame width. The weaker reaction rate and reduced heat transfer are the essential factors that result in a decreasing flame spread rate at lower pressures. In addition, a simplified correlation between the flame spread rate, pressure, and wire configuration in the form of V f ∝ ( P 2 L 3 ) 0.65 is proposed to predict flame propagation along an electrical wire. Moreover, the influence of the metal core on the flame behavior was observed based on the different heat transfer mechanisms in the flame front zone. All results contribute to the safe operation of electrical wires.

中文翻译：

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变压下水平电线火焰传播的实验研究

摘要 电线聚合物绝缘层上的火焰传播行为会点燃相邻的可燃物并增加火灾的规模。在这项研究中，在不同压力下，对聚乙烯 (PE) 绝缘电线的火焰传播行为进行了理论和实验研究。实验首次在三个不同海拔（64、76 和 100 kPa）的城市和一个新设计的低压室（7.5-101.3 kPa）中进行。检查和讨论了火焰形态、结构和蔓延速度。结果表明压力显着影响火焰传播行为。随着压力的增加，火焰照度增加，火焰形状发生变化，而平均火焰高度随着平均火焰宽度的减小而单调增加。较弱的反应速率和降低的传热是导致较低压力下火焰蔓延速率降低的重要因素。此外，还提出了火焰蔓延速率、压力和电线配置之间的简化相关性，形式为 V f ∝ (P 2 L 3 ) 0.65，以预测火焰沿电线的传播。此外，根据火焰前沿区的不同传热机制，观察了金属芯对火焰行为的影响。所有结果都有助于电线的安全运行。建议使用 65 来预测火焰沿电线的传播。此外，根据火焰前沿区的不同传热机制，观察了金属芯对火焰行为的影响。所有结果都有助于电线的安全运行。建议使用 65 来预测火焰沿电线的传播。此外，根据火焰前沿区的不同传热机制，观察了金属芯对火焰行为的影响。所有结果都有助于电线的安全运行。