本文關(guān)鍵詞： 彎管 天然氣 壓力模型 壁厚公式 熱推工藝　出處：《山東建筑大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：彎管在工業(yè)領(lǐng)域具有非常重要的用途,是石油、化工、航海、航空和核工業(yè)領(lǐng)域的重要零部件。當(dāng)流體流經(jīng)管道的彎管段時,會對彎管凸邊形成較大沖擊,在彎管凸邊形成增壓區(qū)、凹邊一側(cè)反而形成減壓區(qū),加之實際的管道輸送網(wǎng)絡(luò)大多需要在高溫、高壓的環(huán)境下運行,因此彎管往往成為管道的應(yīng)力集中部位。由于加工工藝的限制,彎管加工成形時凸邊管壁受拉減薄或開裂、凹邊管壁受壓增厚或起皺等問題,則成為導(dǎo)致彎管破壞的主要原因。因此,對彎管進行準確的受力分析便成為彎管壁厚設(shè)計的重要前提。本文利用FLUENT流體軟件對天然氣流經(jīng)彎管的流動特性進行了數(shù)值模擬,分析了各參數(shù)對彎管內(nèi)壁面壓強的影響規(guī)律,并給出了90°彎管內(nèi)壓三維分布模型。通過對彎管進行受力分析,分別求出了軸向應(yīng)力、環(huán)向應(yīng)力、徑向應(yīng)力三個主應(yīng)力及變壁厚等強度彎管壁厚設(shè)計公式。借助于有限元模擬軟件ABAQUS對牛角芯棒熱推成形工藝進行模擬分析,并比較了不同的工藝參數(shù)對彎管壁厚的影響,得出了熱推彎管成形工藝的最佳工藝參數(shù)。具體研究內(nèi)容如下：(1)應(yīng)用計算流體力學(xué)軟件FLUENT對天然氣在90°彎管內(nèi)的流動特性進行仿真模擬,并分析了彎管內(nèi)壁面壓強的分布規(guī)律。(2)改變天然氣的流動參數(shù)、彎管幾何參數(shù),在48種工況下對天然氣在彎管內(nèi)的流動進行模擬,建立彎管內(nèi)壓的數(shù)據(jù)庫,并分析了不同參數(shù)的變化對彎管內(nèi)壓的影響。(3)應(yīng)用彎管內(nèi)壓數(shù)據(jù)庫,借助于數(shù)學(xué)擬合軟件1 stOpt建立彎管內(nèi)壁面壓強的三維模型。結(jié)合彎管內(nèi)壓模型對彎管的應(yīng)力狀態(tài)求解,利用第三強度理論得出變壁厚等強度彎管的壁厚設(shè)計公式。(4)應(yīng)用有限元軟件ABAQUS模擬了牛角芯棒熱推成形工藝,通過分析不同工藝參數(shù)對壁厚分布的影響,實現(xiàn)了對工藝參數(shù)速度v、溫度T、摩擦系數(shù)f的優(yōu)化,得出了最佳的工藝參數(shù)。
[Abstract]:Bends are very important parts in the fields of petroleum, chemical industry, navigation, aviation and nuclear industry. When the fluid flows through the pipe section of the pipe, it will form a great impact on the convex edge of the bend pipe. A pressurized zone is formed at the convex edge of a curved pipe and a decompression zone is formed on the concave side. In addition, most of the actual pipeline transportation networks need to operate under high temperature and high pressure. Because of the limitation of the processing technology, the bulge tube wall is thinned or cracked, and the concave pipe wall is compressed and thickened or wrinkled due to the limitation of the processing technology. It becomes the main cause of the failure of the elbow. The accurate force analysis of the bend pipe becomes an important prerequisite for the design of the wall thickness of the bend pipe. In this paper, the flow characteristics of natural gas flowing through the bend pipe are numerically simulated by using the FLUENT fluid software. The influence of various parameters on the pressure on the inner wall of the curved pipe is analyzed, and a three-dimensional distribution model of the internal pressure of the 90 擄bend is given. The axial stress and the circumferential stress are obtained by the analysis of the force on the elbow. The design formula of radial stress for three principal stresses and variable wall thickness for curved tubes with equal strength is presented. The hot push forming process of corrugated corrugated corrugated bars is simulated and analyzed by means of finite element simulation software ABAQUS. The influence of different process parameters on the wall thickness of the curved pipe is compared. The optimum technological parameters of the hot push tube forming process are obtained. The specific research contents are as follows: 1) the flow characteristics of natural gas in 90 擄bend pipe are simulated by the computational fluid dynamics software FLUENT. The distribution law of pressure on the inner wall of curved pipe is analyzed. (2) changing the flow parameters of natural gas and geometric parameters of the bend pipe, the flow of natural gas in the bend pipe is simulated under 48 working conditions. The database of internal pressure of bend pipe is established, and the influence of different parameters on internal pressure of bend pipe is analyzed. With the help of the mathematical fitting software 1 stOpt, the three-dimensional model of the pressure on the inner wall of the bend pipe is established, and the stress state of the bend pipe is solved by combining the internal pressure model of the bend pipe. According to the third strength theory, the design formula of the wall thickness of the curved pipe with variable wall thickness is obtained. (4) the hot-push forming process of the corrugated corrugated rod is simulated by using the finite element software ABAQUS. By analyzing the influence of different process parameters on the distribution of wall thickness, the optimum process parameters, such as velocity v, temperature T and friction coefficient f, are obtained.
【學(xué)位授予單位】：山東建筑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TE973

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本文編號：1464211