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空间飞行器冷屏是一种包裹在高速飞行器外的基于相变制冷的装置,可以降低高速飞行器在太空飞行时的红外辐射特性。冷屏在发射前需要进行低温制冷剂加注。如果没有保护装置,在地面加注时会引起冷屏表面严重结霜,恶化冷屏表面红外辐射特性。设计了一种由保温层和氮气保护层组成的防霜结构。氮气保护层利用氮气在低温下不易凝结的特性,保护冷屏外壳使不结霜;保温层利用保温材料的热阻特性,使保温层外壁温度在当地露点温度以上,从而防止空气中水蒸气在保温层外壁凝结。建立了氮气保护气填充速度随时间变化的关系式。实验表明,冷屏表面和保温层外壳均实现了零结霜,取得了很好的防霜效果。
Spacecraft cold screen is a phase-change refrigeration device wrapped outside the high-speed aircraft, which can reduce the infrared radiation characteristics of high-speed aircraft in space flight. Cold screen in the launch before the need for low temperature refrigerant filling. If there is no protective device, it will cause serious frosting on the surface of cold screen when filling the ground, which will worsen the infrared radiation characteristics of cold screen surface. A frost protection structure consisting of a thermal insulation layer and a nitrogen protective layer was designed. The nitrogen protective layer utilizes the property that the nitrogen is not easy to condense at low temperature and protects the cold-screen housing from frosting. The thermal insulation layer utilizes the thermal resistance property of the thermal insulating material to make the temperature of the outer wall of the thermal insulating layer above the local dew point temperature so as to prevent the water vapor in the air from Insulation outer wall condensation. The relationship between the filling velocity and the time of nitrogen gas was established. Experiments show that the cold-screen surface and the insulation shell have achieved zero frost, and achieved good anti-frost effect.