航天器真空热试验的负压过冷系统设计

摘要

航天器外部组件(如太阳电池阵)进行真空热试验时,其表面温度需降至-170℃,一般的空间环境模拟器配备的液氮及热沉系统很难将试验件冷却至-170℃,为进一步降低试验温度,研制一种负压过冷系统.系统由过冷器、加热系统、压力控制系统和管路连接系统组成,利用液氮在真空环境中具有更低饱和温度的特性以获得比常规液氮系统更低的液氮温度.设计了负压过冷系统,搭建了工程样机,并且进行了调试试验.试验验证结果表明,过冷器出口温度低于-200℃,针对-170℃温区的试验,可缩短试验周期40%.%The spacecraft external components(such as solar array)surface temperature is needed to be reduced to-170℃during thermal vacuum test. The specimen is hard to be cooled to-170℃ by the liquid nitrogen and thermal shroud system of conventional space environment simulator. A negative pressure subcooling system was developed to further re-duce the test temperature. The system consists of subcooler,heating system,pressure control system and piping system, utilizes liquid nitrogen to have a lower saturation temperature at negative pressure to obtain a lower liquid nitrogen temper-ature than conventional liquid nitrogen systems. Negative pressure subcooling system was designed in this paper,and an engineering prototype was built and tested. The result of thermal tests shows that the outlet temperature of subcooler can reach lower than-200℃and the period of thermal tests with the lowest temperature of -170℃can be minimized to 40%.