卫星静电热开关辐射散热器热性能分析

运行于轨道的卫星的温度由它接受的阳光照射、来自星球的辐射和它自身向宇宙冷黑背景辐射热平衡所决定。因此，卫星表面材料的辐射特性对卫星的温度有非常大的影响。具有适当发射吸收比的表面材料，可以使在轨飞行的卫星平衡在合适的温度，这是目前卫星热控的基础。然而，由于飞行姿态、轨道、星上设备发热状态、特殊环境（如月球和深空探测）造成卫星所处的外热流条件有很大的差异，固定发射吸收比的表面散热元件OSR已经在很大程度上限制了卫星的热控设计和整星的性能。静电热开关辐射散热器（ESR）是一种可变热导辐射热控元件，通过静电力控制高发射率复合薄膜与基板的热接触热阻来调节卫星温度。薄膜下拉时为导通状态，此时ESR等效发射率高，热量传导到ESR表面进行散热；薄膜不下拉时为关断状态，此时ESR等效发射率低，热量只能辐射到ESR表面散热。ESR相对于电致变色和热致变色元件具有结构简单、可靠性高、发射率变化转换快等特点。对ESR进行了详细热分析，提出了提高其性能的诸多措施，对ESR的研制具有一定的指导意义。

THERMAL PERFORMANCE ANALYSIS OF ELECTROSTATIC SWITCHED RADIATOR FOR SATELLITE

The temperature of the satellite in orbit is determined by the balance between its energy absorption of radiation （mainly from the sun and other star）and loss of energy via radiation to the cold-black universe. Therefore, the material characteristic of the satellite surface is very important. If the absorbing-radiating ratio of the satellite surface material is reasonable, the balance temperature is suitable for equipment on satellite. However, because of the transformation in flight attitude, orbit, satellite equipment, special environment （such as the moon and the deep space exploration）, the heat transfer around satellite change greatly. In these conditions, the thermal control devices with fixed absorbing-radiating ratio like OSR have the serious limitation in satellite thermal control design and performance of the entire satellite. In this paper, we analyze an active thermal control device, termed Electrostatic switched radiator （ESR）. ESR is a variable thermal conductivity device which uses electrostatic hold-down of a high emissivity composite thin film to control satellite temperature. The electrostatic hold-down switches the mode of heat transfer from conduction to radiation. The effect is a large change in apparent emissivity. Application of the voltage results in the high emissivity state while removal gives the low emissivity state. The ESR has the advantages of simple structure, high reliability and fast change of emissivity compared to the electrochromic device and thermochromic device. In this paper, we fred out several ways to improve the thermal performance of ESR. All these methods have general guiding significance to the ESR fabricating.