太阳望远镜的倒锥导流式热光阑研制

Development of the inverted-cone diversion type heat-stop for solar telescopes

对于大口径地基开放式太阳望远镜,热光阑温升将导致其像质劣化。尤其是,热光阑通光孔紧挨成像光束,其与环境的温度差对像质影响很大。这是中国巨型太阳望远镜(Chinese Giant Solar Telescope,CGST)计划面临的诸多问题之一。解决热光阑温控问题的具体方法是设计整体冷却效率高且在关键位置得到进一步强化的热光阑结构,以达到温控均匀的目的。本文提出倒锥导流式热光阑设计方案,该方案有利于降低通光孔位置温度,使温度极高点离开通光孔。对流换热系数和光阑温度场仿真结果证明此方案明显优于目前常用的方法。倒锥导流式热光阑的极限温升为3℃,优于GREGO的极限温升(7℃);实测温度场与仿真温度场进行对照,结果在误差范围内。结果证明导流式倒锥结构具有较好的温控效果。

For large-aperture ground-based open-structure solar telescopes,an increase in heat-stop temperat-ure will result in deterioration of image quality.In particular,heat-stop,located closely to the light-passing hole,has a great influence on image quality.This is one of the problems for the Chinese Giant Solar Telescope(CGST)development plan.For solving the heat-stop temperature control problem,the overall cooling efficiency should be high and further strengthen is implemented at key locations to achieve uniform temperature control.According to the above problem,an Inverted-Cone Diversion Type(ICDT)heat-stop design is proposed,which can reduce the temperature of the light-passing hole and make the hottest area away from the light-passing hole.The simulation results of cooling efficiency and heat-stop temperature field show that this scheme is obviously superior to its predecessor.The temperature of ICDT′s heat-stop is up to 3℃above ambient,which is better than GREGO′s temperature difference of 7℃.The research team also carried out the heat-stop temperature field measurement experiment and verified the accuracy of the temperature field simulation′s results showing that ICDT heat-stop design has good temperature control capability.