【摘要】：射電望遠(yuǎn)鏡，又稱為射電天線，是收集、捕捉宇宙天體暗弱輻射的重要工具，對(duì)射電天文學(xué)的發(fā)展具有巨大的推動(dòng)作用。全可動(dòng)射電望遠(yuǎn)鏡主要由主副反射面、背架結(jié)構(gòu)、方位座架、俯仰機(jī)構(gòu)、撐腿等組成。靈敏度和分辨率是衡量射電望遠(yuǎn)鏡工作性能的兩項(xiàng)基本指標(biāo)，增大主反射面的口徑是改善射電望遠(yuǎn)鏡工作性能的有效途徑。然而，對(duì)于大口徑或高精度射電望遠(yuǎn)鏡，由太陽(yáng)輻射、空氣對(duì)流等復(fù)雜環(huán)境因素共同作用引起的非均勻溫度荷載如同重力荷載與風(fēng)荷載，是影響射電望遠(yuǎn)鏡工作性能的重要因素。因此，對(duì)射電望遠(yuǎn)鏡結(jié)構(gòu)進(jìn)行真實(shí)環(huán)境下的溫度場(chǎng)數(shù)值模擬，具有良好的理論研究意義及工程應(yīng)用價(jià)值。本文主要開展了以下幾方面工作： 1、射電望遠(yuǎn)鏡結(jié)構(gòu)的日照陰影分析 以大型通用有限元軟件ANSYS為平臺(tái)，采用FORTRAN語(yǔ)言編寫了射電望遠(yuǎn)鏡結(jié)構(gòu)日照陰影分析模塊CPOS(Calculation Program of Shadow)，并以上海65m射電望遠(yuǎn)鏡結(jié)構(gòu)為例，分析了望遠(yuǎn)鏡結(jié)構(gòu)在夏至日一天中不同時(shí)刻各構(gòu)件的日照陰影，計(jì)算了各桿件的日照系數(shù)。 2、射電望遠(yuǎn)鏡結(jié)構(gòu)熱環(huán)境的確定 綜合分析了射電望遠(yuǎn)鏡結(jié)構(gòu)復(fù)雜的熱環(huán)境，確定了射電望遠(yuǎn)鏡結(jié)構(gòu)與周圍環(huán)境的熱平衡關(guān)系及熱量交換方式，提出了太陽(yáng)輻射、周圍環(huán)境長(zhǎng)波輻射等環(huán)境因素的簡(jiǎn)化計(jì)算方法，編制了考慮時(shí)間邊界條件的計(jì)算程序，為后續(xù)的溫度場(chǎng)有限元分析奠定基礎(chǔ)。 3、上海65m射電望遠(yuǎn)鏡結(jié)構(gòu)非均勻溫度場(chǎng)分析 以上海65m射電望遠(yuǎn)鏡結(jié)構(gòu)為分析對(duì)象，建立了真實(shí)環(huán)境下的望遠(yuǎn)鏡結(jié)構(gòu)溫度場(chǎng)參數(shù)化有限元分析模型，綜合考慮了太陽(yáng)輻射、陰影遮擋、空氣對(duì)流等時(shí)變作用，通過時(shí)程分析，計(jì)算了不同時(shí)刻、不同工作旋轉(zhuǎn)角下望遠(yuǎn)鏡結(jié)構(gòu)的溫度場(chǎng)，，總結(jié)了溫度場(chǎng)分布的時(shí)間特性和空間特性，重點(diǎn)對(duì)比分析了不同工作旋轉(zhuǎn)角下不考慮和考慮桿件遮擋兩種情況下背架結(jié)構(gòu)的均方根溫度差。 4、上海65m射電望遠(yuǎn)鏡“太陽(yáng)灶”問題研究 解析了射電望遠(yuǎn)鏡結(jié)構(gòu)“太陽(yáng)灶”問題的形成原因，分析了光線投影算法計(jì)算“太陽(yáng)灶”問題的主要步驟，建立了上海65m射電望遠(yuǎn)鏡“太陽(yáng)灶”問題的數(shù)值分析模型，對(duì)不同工作旋轉(zhuǎn)角下的“太陽(yáng)灶”問題進(jìn)行了參數(shù)化有限元分析，重點(diǎn)統(tǒng)計(jì)了不同工作旋轉(zhuǎn)角下“太陽(yáng)灶”問題的產(chǎn)生時(shí)間、持續(xù)時(shí)間以及副反射面的最高溫度。
[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.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：P111.44;TU31

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本文編號(hào)：2230388