卫星搭载导线着火前期特性实验研究

导线绝缘层的过热及由此发生的着火和燃烧是载人航天飞行器中引起火灾的主要原因.研究微重力下导线绝缘层的可燃性对于预防飞船中火灾的发生有重要意义.本文描述了SJ-8卫星搭载实验项目导线着火前期特性硬件研制以及实验情况.实验中获得了导线着火前期的温度和辐射特性.在搭载实验中,研究了导线过载电流和导线捆绑方式对导线绝缘层着火前期特性的影响.同时将微重力下的实验结果与地面功能模拟的实验结果进行了对比.实验结果表明,微重力环境下自然对流基本消失,导线和电子电气元件的散热情况恶化,在过载的情况下,就可能过热,从而导致失火.搭载实验中导线先期着火征兆的获得,将为开发我国微重力下的着火监测和早期报警装置提供新的技术途径,为我国载人航天飞行器内安全防火的工程技术工作提供科学依据和基础数据资料. 

Study on Fire Initiation of Wire Insulations on Board the Satellite

The damage and overheating of wire insulation is the main ignition source in the fire incidents of the manned spacecraft in microgravity.Anyway,until now the study on wire insula- tion flammability in microgravity is limited.Thus the study on fire initiation of wire insulation in microgravity is of importance for fire safety in spacecraft.The experimental hardware was devel- oped to perform the experiments of fire initiation of wire insulation caused by overload on board the S J-8 China recoverable satellite.In the experiments,the fire initiation characteristics including the temperature and radiation characteristics of the wire insulations were presented.The temperature histories of the wire insulation in microgravity and the low-pressure environment in normal-gravity were obtained.Effects of overloaded currents on the fire initiation were investigated for different wire coiled states.The results indicate that the natural convection almost vanished and the heat loss of the electric components decreased in the microgravity environment.It might cause overheat of the electric components and then results in fire,and thus the fire risks of wire in the microgravity condition are much more dangerous than that in normal-gravity under the condition of overload.