超大口径射电望远镜温度场分析

随着天线口径增大、频率升高,日照热对其性能的影响愈发严重.针对待建的新疆110 m大口径全可动射电望远镜,建立其热分析有限元模型,研究天线在夏至日不同太阳时刻的温度场分布特性.结果如下:一天中,主反射面的最高温度可达42.86℃,出现在14时,同时刻撑腿的温度也达到峰值,为41.74℃.背架水平分区温差在5时、18时、19.5时均超过1℃,会对天线指向性能产生较大影响.夜间天线结构温度分布亦不均匀,俯仰结构的温差明显高于其他构件,最大温差为6.42℃,通过数值模拟与试验相结合的方法,证明了构件的壁厚差异是导致结构夜间温差较大的主要原因.

Analysis of Temperature Field of Very Large Aperture Radio Telescope

With the increase of antenna aperture and frequency, the influence of solar heat on its performance becomes more and more serious. In this paper, the thermal model of the 110m aperture radio telescope to be built in Xinjiang is established to study its temperature field characteristics on the summer solstice. The results are as follows: during the day, the highest temperature of the main reflector can reach 42.86^\circC, which appears at 14 o''clock, and the temperature of the legs also reaches the peak of 41.74^\circC at the same time. The horizontal temperature difference of the back frame will exceed 1^\circC at 5, 18 and 19.5 o''clock, the antenna pointing performance will be greatly affected. The temperature field at night is also not uniform, and the temperature difference of the pitching structure is significantly higher than that of other components, with the maximum temperature difference of 6.42^\circC. Through the method of numerical simulation and test, it is proved that the wall thickness difference of components is the main reason for the large temperature difference at night.