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本文在低压弱浮力环境中模拟了微重力过载电流时导线绝缘层的着火先期过程,研究了压力对绝缘层着火先期特性的影响。结果表明,2 A时,绝缘层的温升率和最终平衡温度随压力降低而不断增大,模拟出了微重力下绝缘层的温升特性;10 A时,随着压力降低,绝缘层存在三种破坏机制;在不同区域压力对着火延迟时间的影响不同。最后,提高环境氧气浓度修正了低压对化学反应速率的抑制。结果表明,当压力在一定范围内降低时,随着氧气浓度的提高,绝缘层的着火极限范围拓宽,着火延迟时间缩短,可以初步模拟微重力下绝缘层的着火先期过程。
This paper simulates the pre-ignition process of wire insulation in low-pressure and weak buoyancy environment and studies the influence of pressure on the characteristics of fire-before-ignition of insulation layer. The results show that the temperature rise rate and the final equilibrium temperature of the insulation layer increase with the decrease of pressure at 2 A, and the temperature rise characteristics of the insulation layer under simulated microgravity are simulated. With the decrease of pressure, the insulation layer exists at 10 A Three types of damage mechanisms; different regions have different effects on fire delay time. Finally, increasing the ambient oxygen concentration corrects the inhibition of the chemical reaction rate by low pressure. The results show that with the increase of oxygen concentration, the ignition limit of insulating layer broadens and the ignition delay time shortens when the pressure is reduced within a certain range, and the pre-ignition process of insulating layer under microgravity can be preliminarily simulated.