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巨型射電望遠(yuǎn)鏡風(fēng)荷載特性的數(shù)值模擬研究

發(fā)布時(shí)間:2018-11-29 08:46
【摘要】:巨型全可動(dòng)射電望遠(yuǎn)鏡項(xiàng)目的建設(shè)問(wèn)題,是當(dāng)前我國(guó)射電天文學(xué)領(lǐng)域關(guān)注的熱點(diǎn)之一。風(fēng)荷載的作用會(huì)降低望遠(yuǎn)鏡反射面的形狀擬合精度,影響其觀測(cè)性能。目前,國(guó)內(nèi)外對(duì)于望遠(yuǎn)鏡結(jié)構(gòu)風(fēng)荷載特性的研究還非常有限。本文基于CFD(計(jì)算流體力學(xué))數(shù)值模擬方法研究望遠(yuǎn)鏡結(jié)構(gòu)的風(fēng)荷載特性,對(duì)影響風(fēng)荷載特性的因素進(jìn)行了參數(shù)分析,并基于研究結(jié)果對(duì)65m口徑望遠(yuǎn)鏡在平均風(fēng)荷載作用下的精度進(jìn)行了求解。 本文主要內(nèi)容包括: 1.采用不同湍流模型對(duì)望遠(yuǎn)鏡球形保護(hù)罩和1.5米口徑拋物面天線結(jié)構(gòu)的風(fēng)場(chǎng)進(jìn)行了數(shù)值模擬,并與規(guī)范方法和風(fēng)洞試驗(yàn)結(jié)果進(jìn)行了對(duì)比分析,最終確定了采用RSM(雷諾應(yīng)力)模型對(duì)望遠(yuǎn)鏡結(jié)構(gòu)風(fēng)場(chǎng)進(jìn)行數(shù)值模擬的方案。 2.基于CFD數(shù)值模擬方法和RSM湍流模型,對(duì)口徑110米、焦徑比0.32的射電望遠(yuǎn)鏡結(jié)構(gòu)在B類地貌下的風(fēng)場(chǎng)進(jìn)行了數(shù)值模擬,研究了其風(fēng)荷載特性(包括風(fēng)力系數(shù)、平均風(fēng)壓分布以及局部極值風(fēng)壓作用),并考慮了俯仰角和風(fēng)向角的影響。給出了望遠(yuǎn)鏡結(jié)構(gòu)分區(qū)平均風(fēng)壓系數(shù)和分區(qū)風(fēng)荷載體型系數(shù),以方便工程應(yīng)用。最后基于流場(chǎng)繞流特性的分析,對(duì)望遠(yuǎn)鏡結(jié)構(gòu)最不利受力姿態(tài)進(jìn)行了預(yù)測(cè)。 3.多因素、多水平的組織正交數(shù)值風(fēng)洞試驗(yàn),對(duì)影響望遠(yuǎn)鏡結(jié)構(gòu)風(fēng)荷載特性的若干因素進(jìn)行了參數(shù)分析。其中,幾何參數(shù)-口徑選取D=65m、D=90m、D=110m三種情況,幾何參數(shù)-焦徑比選取f/D=0.3、f/D=0.5兩種情況;風(fēng)環(huán)境參數(shù)選取B類地貌和C類地貌兩種情況;工作參數(shù)-俯仰角選取0度、30度、60度、90度共四種情況,工作參數(shù)-風(fēng)向角選取0度、30度、60度、90度、120度、150度、180度共七種情況;并就俯仰軸高度和風(fēng)速(雷諾數(shù))的影響進(jìn)行了分析。明確了各影響因素的范圍和大小,,并給出了風(fēng)荷載特性的相關(guān)規(guī)律,為工程實(shí)際中有針對(duì)性的進(jìn)行抗風(fēng)設(shè)計(jì)提供了參考依據(jù)。 4.基于CFD數(shù)值模擬結(jié)果,對(duì)65m口徑射電望遠(yuǎn)鏡在風(fēng)荷載作用下的最佳法向偏差和整體位移進(jìn)行了計(jì)算求解,評(píng)估了風(fēng)荷載作用對(duì)望遠(yuǎn)鏡結(jié)構(gòu)精度的影響。
[Abstract]:The construction of giant fully movable radio telescope is one of the hotspots in the field of radio astronomy in China. The effect of wind load will reduce the shape fitting accuracy of the reflector of the telescope and affect its observation performance. At present, the research on the wind load characteristics of telescope structures is very limited at home and abroad. In this paper, based on CFD (computational fluid dynamics) numerical simulation method, the wind load characteristics of telescope structures are studied, and the factors affecting the wind load characteristics are analyzed. Based on the research results, the accuracy of the 65m telescope under the action of average wind load is solved. The main contents of this paper are as follows: 1. Different turbulence models are used to simulate the wind field of the spherical protective cover and 1.5 m paraboloid antenna structure of the telescope, and the results are compared with those of the standard method and the wind tunnel test results. Finally, a numerical simulation scheme for wind field of telescope structure using RSM (Reynolds stress) model is proposed. 2. Based on the CFD numerical simulation method and the RSM turbulence model, the wind field of the radio telescope with a diameter of 110m and a focal diameter ratio of 0.32 is numerically simulated under the B geomorphology, and the wind load characteristics (including wind coefficient) are studied. The distribution of mean wind pressure and local extreme wind pressure) and the influence of pitch angle and wind direction angle are taken into account. The average wind pressure coefficient and the wind load shape coefficient of the telescope structure are given in order to facilitate the engineering application. Finally, based on the analysis of the flow characteristics around the flow field, the most unfavorable attitude of the telescope structure is predicted. 3. Several factors affecting the wind load characteristics of telescope structures are analyzed by multi-factor, multi-level tissue orthogonal numerical wind tunnel test. Among them, there are three kinds of cases: the geometric parameter and caliber are chosen, the geometric parameter and the focal diameter ratio are chosen, the geometric parameter and the focal diameter ratio are chosen, and the wind environment parameter is chosen as the type B geomorphology and the C type geomorphology, and the wind environment parameter is chosen in the following two cases: class B geomorphology and type C geomorphology. The working parameter-pitch angle is 0, 30, 60 and 90 degrees, and the working parameter-wind direction angle is 0, 30, 60, 90, 120, 150 and 180 degrees respectively, and the working parameter-wind direction angle is 0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees and 180 degrees. The influence of pitch axis height and wind speed (Reynolds number) is analyzed. The range and magnitude of the influencing factors are defined, and the related laws of wind load characteristics are given, which provides a reference for the engineering practice to carry out the wind resistance design. 4. Based on the CFD numerical simulation results, the optimum normal deviation and global displacement of 65m radio telescope under wind load are calculated and solved, and the influence of wind load on the structure accuracy of the telescope is evaluated.
【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)】:TU312.1;P111.44

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