临近空间光学遥感器热设计

Thermal design for near space optical remote sensor

为了保证光学遥感器在平流层空间热环境中安全可靠地工作,对工作在平流层内的光学遥感器进行了热分析。分析了运行在25 km以上空间的飞艇要经历的平流层的环境特点,包括平流层内的大气密度、温度分布等。建立了平流层光学遥感器的传热数学模型,分析了遥感器的迎风面、侧面和背风面在顺风飞行和逆风飞行情况下的对流情况,计算得到在逆风飞行和顺风飞行时迎风面、侧面、背风面的对流换热系数分别为5.009,8.259,3.33 W/(m2.K)和2.609,2.959,1.005 W/(m2.K)。最后,根据稳态换热平衡方程,利用热分析软件分析了光学遥感器在两种极端工况下的温度场分布。结果显示,采用热控措施后光学遥感器的轴向温差从15°减小到了2.7℃,飞艇与空气的对流换热系数随着它们之间的相对速度的增大而增大。结果表明,本文采用的热控手段可以减小遥感器的温差,这为进一步开展平流层光学遥感器的热分析奠定了基础。

In order to maintain the high reliability of Space Optical Remote Sensors（SORS） in a stratospheric thermal environment,the thermal-analysis for a SORS was carried out.The stratospheric environment over 25 km was described,including the atmosphere pressure,density and temperature,then a thermal analysis model was established.The convection heat transfer coefficients on the forward face,side surface and rear surface of SORS were calculated.Results show that the coefficients on the three surfaces are 5.009,8.259 and 3.33 W/（m^2·K） respectively when the airship sails against the wind,and 2.609,2.959 and 1.005 W/（m^2·K） respectively when the airship sails before the wind.Furthermore,the two temperature profiles in extreme conditions,the high temperature condition and the low temperature condition,were analyzed with the software of IDEAS.Experimental results demonstrate that the axial temperature difference of the SORS after thermal control has decreased from 15～2.7 ℃ and the convection heat transfer coefficients of an airship to the wind are increased with the increase of their relative speeds.It is concluded that the thermal control method is effective and obtained temperature data can provide references for the thermal distortion analysis and the selection of thermal control strategy.