巨型射电望远镜结构非均匀温度场研究
发布时间：2018-09-08 11:31
【摘要】：射电望远镜，又称为射电天线，是收集、捕捉宇宙天体暗弱辐射的重要工具，对射电天文学的发展具有巨大的推动作用。全可动射电望远镜主要由主副反射面、背架结构、方位座架、俯仰机构、撑腿等组成。灵敏度和分辨率是衡量射电望远镜工作性能的两项基本指标，增大主反射面的口径是改善射电望远镜工作性能的有效途径。然而，对于大口径或高精度射电望远镜，由太阳辐射、空气对流等复杂环境因素共同作用引起的非均匀温度荷载如同重力荷载与风荷载，是影响射电望远镜工作性能的重要因素。因此，对射电望远镜结构进行真实环境下的温度场数值模拟，具有良好的理论研究意义及工程应用价值。本文主要开展了以下几方面工作： 1、射电望远镜结构的日照阴影分析 以大型通用有限元软件ANSYS为平台，采用FORTRAN语言编写了射电望远镜结构日照阴影分析模块CPOS(Calculation Program of Shadow)，并以上海65m射电望远镜结构为例，分析了望远镜结构在夏至日一天中不同时刻各构件的日照阴影，计算了各杆件的日照系数。 2、射电望远镜结构热环境的确定 综合分析了射电望远镜结构复杂的热环境，确定了射电望远镜结构与周围环境的热平衡关系及热量交换方式，提出了太阳辐射、周围环境长波辐射等环境因素的简化计算方法，编制了考虑时间边界条件的计算程序，为后续的温度场有限元分析奠定基础。 3、上海65m射电望远镜结构非均匀温度场分析 以上海65m射电望远镜结构为分析对象，建立了真实环境下的望远镜结构温度场参数化有限元分析模型，综合考虑了太阳辐射、阴影遮挡、空气对流等时变作用，通过时程分析，计算了不同时刻、不同工作旋转角下望远镜结构的温度场，，总结了温度场分布的时间特性和空间特性，重点对比分析了不同工作旋转角下不考虑和考虑杆件遮挡两种情况下背架结构的均方根温度差。 4、上海65m射电望远镜“太阳灶”问题研究 解析了射电望远镜结构“太阳灶”问题的形成原因，分析了光线投影算法计算“太阳灶”问题的主要步骤，建立了上海65m射电望远镜“太阳灶”问题的数值分析模型，对不同工作旋转角下的“太阳灶”问题进行了参数化有限元分析，重点统计了不同工作旋转角下“太阳灶”问题的产生时间、持续时间以及副反射面的最高温度。
[Abstract]:Radio telescopes, also known as radio antennas, are important tools for collecting and capturing dark weak radiation from cosmic objects, and play an important role in the development of radio astronomy. The fully movable radio telescope is mainly composed of main and secondary reflector, back frame structure, azimuth frame, pitching mechanism, support leg and so on. Sensitivity and resolution are two basic indexes to evaluate the performance of radio telescopes. Increasing the aperture of the main reflector is an effective way to improve the performance of radio telescopes. However, for large aperture or high precision radio telescopes, inhomogeneous temperature loads caused by complex environmental factors, such as solar radiation and air convection, are similar to gravity and wind loads. It is an important factor that affects the performance of radio telescope. Therefore, numerical simulation of the temperature field of radio telescope structure in real environment has good theoretical significance and engineering application value. The main work of this paper is as follows: 1. The sunlight shadow analysis of the radio telescope structure is based on the large universal finite element software ANSYS. In this paper, FORTRAN language is used to compile the module CPOS (Calculation Program of Shadow), for analyzing the sunshine shadow of the radio telescope structure. Taking the 65m radio telescope structure in Shanghai as an example, the sunlight shadow of each component of the telescope structure at different times of the day of the Summer Solstice is analyzed. The sunshine coefficient of each member is calculated. 2. The determination of the thermal environment of the radio telescope structure and the comprehensive analysis of the complex thermal environment of the radio telescope structure are given. The heat balance relationship between radio telescope structure and surrounding environment and the heat exchange mode are determined. A simplified calculation method for environmental factors, such as solar radiation, ambient long wave radiation, and so on, is put forward, and a calculation program considering time boundary conditions is compiled. 3. The non-uniform temperature field analysis of the 65m radio telescope structure in Shanghai takes the structure of the Shanghai 65m radio telescope as the object of analysis. The parameterized finite element analysis model of the temperature field of the telescope structure in real environment is established. The time-varying effects of solar radiation, shadow occlusion and air convection are comprehensively considered. The temperature field of telescope structure at different working angles is summarized, and the temporal and spatial characteristics of the temperature field distribution are summarized. The root mean square temperature difference of the back frame structure without considering and considering the bar occlusion under different working rotation angles is compared and analyzed. 4. The study solution of the Solar cooker for the 65m Radio Telescope in Shanghai The causes of the problem of "solar cooker" in the radio telescope structure are analyzed. In this paper, the main steps of ray projection algorithm to calculate the "solar cooker" problem are analyzed, and the numerical analysis model of the "solar stove" problem of Shanghai 65m radio telescope is established. The problem of "solar cooker" under different working rotation angles is analyzed by parameterized finite element method, and the time, duration and maximum temperature of the accessory reflector are calculated.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P111.44;TU31
本文编号：2230388
[Abstract]:Radio telescopes, also known as radio antennas, are important tools for collecting and capturing dark weak radiation from cosmic objects, and play an important role in the development of radio astronomy. The fully movable radio telescope is mainly composed of main and secondary reflector, back frame structure, azimuth frame, pitching mechanism, support leg and so on. Sensitivity and resolution are two basic indexes to evaluate the performance of radio telescopes. Increasing the aperture of the main reflector is an effective way to improve the performance of radio telescopes. However, for large aperture or high precision radio telescopes, inhomogeneous temperature loads caused by complex environmental factors, such as solar radiation and air convection, are similar to gravity and wind loads. It is an important factor that affects the performance of radio telescope. Therefore, numerical simulation of the temperature field of radio telescope structure in real environment has good theoretical significance and engineering application value. The main work of this paper is as follows: 1. The sunlight shadow analysis of the radio telescope structure is based on the large universal finite element software ANSYS. In this paper, FORTRAN language is used to compile the module CPOS (Calculation Program of Shadow), for analyzing the sunshine shadow of the radio telescope structure. Taking the 65m radio telescope structure in Shanghai as an example, the sunlight shadow of each component of the telescope structure at different times of the day of the Summer Solstice is analyzed. The sunshine coefficient of each member is calculated. 2. The determination of the thermal environment of the radio telescope structure and the comprehensive analysis of the complex thermal environment of the radio telescope structure are given. The heat balance relationship between radio telescope structure and surrounding environment and the heat exchange mode are determined. A simplified calculation method for environmental factors, such as solar radiation, ambient long wave radiation, and so on, is put forward, and a calculation program considering time boundary conditions is compiled. 3. The non-uniform temperature field analysis of the 65m radio telescope structure in Shanghai takes the structure of the Shanghai 65m radio telescope as the object of analysis. The parameterized finite element analysis model of the temperature field of the telescope structure in real environment is established. The time-varying effects of solar radiation, shadow occlusion and air convection are comprehensively considered. The temperature field of telescope structure at different working angles is summarized, and the temporal and spatial characteristics of the temperature field distribution are summarized. The root mean square temperature difference of the back frame structure without considering and considering the bar occlusion under different working rotation angles is compared and analyzed. 4. The study solution of the Solar cooker for the 65m Radio Telescope in Shanghai The causes of the problem of "solar cooker" in the radio telescope structure are analyzed. In this paper, the main steps of ray projection algorithm to calculate the "solar cooker" problem are analyzed, and the numerical analysis model of the "solar stove" problem of Shanghai 65m radio telescope is established. The problem of "solar cooker" under different working rotation angles is analyzed by parameterized finite element method, and the time, duration and maximum temperature of the accessory reflector are calculated.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P111.44;TU31
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