新疆天文台25 m南山射电望远镜日照温度场研究

Study on the Structural Temperature Field of XAO 25 m NanShan Radio Telescope under Solar Radiation

中国科学院新疆天文台25m南山射电望远镜(25m NSRT)受日照导致天线结构温度不均匀,其指向精度和效率均有一定程度的损失.为研究25m NSRT日照下的热力学特性,构建了晴空下射电望远镜热环境参数和热力学有限元模型,考虑了射电望远镜背架、面板等结构件对光线的反射和遮挡作用,通过比较25m NSRT典型观测工况下各构件的平均温度、均方根温差、单位温差特征距离等特性参数,发现各部件热容量的差异是天线部件间存在大尺度温差现象的主要原因;分析了各类俯仰角和太阳照射角下天线背架结构的温度分布特征,表明日照区域的背架结构温度呈近似线性分布,平均梯度可达0.25℃·m^(-1).

It is observed that both the pointing accuracy and efficiency of the 25 m NanShan Radio Telescope(25 m NSRT),Xinjiang Astronomical Observatory(XAO),Chinese Academy of Sciences,are impaired by the non-uniform temperature field in antenna structure,mainly caused by solar radiation.In order to study the thermal characteristics of 25 m NSRT,we construct thermal environment parameters and thermodynamic finite element model of the NanShan radio telescope,taking into account both the reflection and shielding effects between structural components,such as backup structure and panels.By comparing parameters such as the average temperature,root mean square temperature difference and characteristic dimension under unit temperature difference,it is observed that there are large temperature differences between each component of the telescope due to significant discrepancy in heat capacity of these components.The temperature distribution of antenna backup structure at different elevation and solar angles are analyzed.The results show that in illuminated region the temperature of the backup structure is linearly distributed,with an average gradient of 0.25℃·m^(-1).