本文選題：真空加熱　切入點(diǎn)：觀測(cè)　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：真空技術(shù)以其無污染、無氧化等特點(diǎn)在加熱領(lǐng)域得到了越來越廣泛的應(yīng)用。目前常見的真空加熱設(shè)備大多應(yīng)用于工業(yè)生產(chǎn)。工業(yè)用設(shè)備往往體積龐大,難以搭配高倍顯微鏡對(duì)真空加熱過程進(jìn)行精密監(jiān)測(cè),對(duì)工件或材料在某一溫度下的變形以及表面形貌變化只能憑借經(jīng)驗(yàn)做出定性的估計(jì),難以做出精確的定量判定。為解決此問題,本文研究開發(fā)了真空加熱觀測(cè)實(shí)驗(yàn)平臺(tái),主要研究?jī)?nèi)容包括以下幾個(gè)方面。(1)根據(jù)真空加熱觀測(cè)實(shí)驗(yàn)平臺(tái)技術(shù)指標(biāo)制定整體方案,并對(duì)組成該平臺(tái)的五個(gè)部分進(jìn)行逐一設(shè)計(jì)。真空室部分,設(shè)計(jì)了真空腔體結(jié)構(gòu),計(jì)算了真空腔體壁厚,選取了觀察窗水冷方案并布置了水冷通道。真空泵組部分,設(shè)計(jì)了泵組組合方案,選取了機(jī)械泵與分子泵。真空管路部分,設(shè)計(jì)了連接真空室和泵組的管路。加熱部分采用外熱式加熱,對(duì)加熱絲的結(jié)構(gòu)和排布進(jìn)行了設(shè)計(jì),同時(shí)設(shè)計(jì)制作了保溫層和溫控回路。其它部分則選取了隔振平臺(tái),設(shè)計(jì)定做了高倍顯微鏡。(2)運(yùn)用有限元分析軟件ANSYS Workbench對(duì)真空腔體進(jìn)行有限元分析,仿真結(jié)果表明:在額定載荷下,真空腔體底部變形最大,側(cè)壁抽氣口開孔處應(yīng)力最大,真空腔體底部變形量超過技術(shù)指標(biāo)要求。為了減小變形量,本文采用對(duì)真空腔體底部進(jìn)行加厚和布置加強(qiáng)筋的方案對(duì)真空腔體底部進(jìn)行結(jié)構(gòu)優(yōu)化,并對(duì)兩種優(yōu)化方案從加工工藝到優(yōu)化效果進(jìn)行對(duì)比,最終選取真空腔底部加厚的方案。對(duì)真空腔體側(cè)壁結(jié)構(gòu)進(jìn)行尺寸的參數(shù)化管理,并以真空腔體應(yīng)力值最小、真空腔體質(zhì)量最小為目標(biāo)進(jìn)行多目標(biāo)驅(qū)動(dòng)優(yōu)化,根據(jù)優(yōu)化結(jié)果選取抽氣口管路軸線到真空腔體頂部距離29mm和抽氣口內(nèi)徑尺寸8mm的最佳尺寸組合。(3)對(duì)加工完成的真空加熱觀測(cè)實(shí)驗(yàn)平臺(tái)各部分進(jìn)行搭接、安裝,并對(duì)組裝完成后的設(shè)備進(jìn)行抽真空試驗(yàn)和顯微觀測(cè)試驗(yàn)。結(jié)果表明:真空加熱觀測(cè)實(shí)驗(yàn)平臺(tái)能夠在額定時(shí)間內(nèi)達(dá)到要求真空度,且放大倍數(shù)、視野范圍均符合技術(shù)指標(biāo)要求。對(duì)真空加熱觀測(cè)實(shí)驗(yàn)平臺(tái)的工作區(qū)域進(jìn)行了最高工作溫度下的溫度均勻性測(cè)量。結(jié)果表明:隨著加熱時(shí)間的延長(zhǎng)升溫速度減慢,加熱30min后工作區(qū)域溫度可以穩(wěn)定在最高設(shè)定溫度700℃附近,溫度場(chǎng)進(jìn)入平衡狀態(tài)。對(duì)30min、32min、34min、36min、38min、40min六個(gè)時(shí)刻的測(cè)溫點(diǎn)溫度數(shù)據(jù)進(jìn)行溫度均勻性計(jì)算。結(jié)果表明:這六個(gè)時(shí)刻溫度均勻性分別為5℃、4℃、8℃、5℃、6℃和4℃,符合設(shè)備的溫度技術(shù)指標(biāo)要求。
[Abstract]:Vacuum technology is more and more widely used in the field of heating because of its characteristics of non-pollution and non-oxidation. At present, most of the common vacuum heating equipments are used in industrial production. It is difficult to precisely monitor the vacuum heating process with a high-power microscope. The deformation of the workpiece or material at a certain temperature and the change of the surface morphology can only be qualitatively estimated by experience. It is difficult to make accurate quantitative judgment. In order to solve this problem, a vacuum heating observation experimental platform is developed in this paper. The main research contents include the following aspects. Five parts of the platform are designed one by one. In the vacuum chamber part, the structure of the vacuum chamber is designed, the wall thickness of the vacuum chamber is calculated, the water cooling scheme of the observation window is selected and the water cooling channel is arranged. The combination scheme of pump group is designed, the mechanical pump and molecular pump are selected, and the pipe connecting vacuum chamber and pump group is designed. The heating part is heated by external heat, and the structure and arrangement of heating wire are designed. At the same time, the insulation layer and the temperature control loop are designed and manufactured. In other parts, the vibration isolation platform is selected, and the high-power microscope is designed and customized. The finite element analysis software ANSYS Workbench is used for the finite element analysis of the vacuum cavity. The simulation results show that under rated load, the bottom deformation of vacuum cavity is the largest, and the stress at the opening of sidewall air outlet is the largest. The deformation of vacuum cavity bottom exceeds the requirement of technical index. In this paper, the structure of vacuum cavity bottom is optimized by thickening and reinforcement arrangement at the bottom of vacuum cavity, and the two optimization schemes are compared from processing technology to optimization effect. Finally, the scheme of thickening the bottom of vacuum cavity is selected. The dimension of the side wall of vacuum cavity is parameterized, and the minimum stress of vacuum cavity and the minimum mass of vacuum cavity are taken as the goal of multi-objective driving optimization. According to the optimization results, the optimum dimension combination of 29mm distance between the axis of the exhaust pipe line and the top of the vacuum cavity and 8mm of the inner diameter of the air outlet is selected to lap and install the parts of the vacuum heating observation experimental platform completed by machining. The vacuum test and microscopic observation test of the assembled equipment are carried out. The results show that the vacuum degree required and the magnification of the vacuum heating observation platform can be achieved within the rated time. The range of visual field meets the requirements of technical specifications. The temperature uniformity of the working area of the vacuum heating experimental platform is measured at the highest working temperature. The results show that the heating rate slows down with the prolongation of heating time. After heating for 30 min, the temperature of the working area can be stabilized at the maximum set temperature of 700 鈩，

本文編號(hào)：1597350