毕业论文示例..

2015届毕业设计（论文）题目：加氢反应器弓形格栅数值模拟研究专业：机械工程及自动化班级：机械1107姓名：赵冬指导老师：周建新起讫日期：2015.3.1—2015.6.102015年6月南京工业大学本科生毕业设计（论文）I摘要本文针对某化工厂加氢反应器中弓形格栅催化剂泄露问题，采用ANSYS软件对加氢反应器321不锈钢弓形格栅在使用温度和过温条件下的温度场和变形进行数值模拟研究。模拟过程中按照实际弓形格栅尺寸建立了三维实体模型，并采用顺序耦合对弓形格栅进行了模拟计算。在高温条件下，格栅温度不均匀，最高温差约为70-80℃。由于格栅整体热膨胀，导致格栅产生较大内应力。390℃和486℃条件下对称面上最大压应力分别为-140MPa和-200MPa，冷却到室温变为拉应力，均约为250MPa。在高温390℃条件下，两弓形格栅对称面下端最大间隙为2.64mm，按照计算结果，催化剂不会泄露。在高温486℃条件下，两弓形格栅对称面下端最大间隙为4.58mm，按照模拟计算结果，催化剂两格栅间隙仍不会泄漏，但如果两弓形格栅在装配时有2mm及以上间隙，则两弓形格栅间隙将大于6.58mm，将会导致催化剂仍泄漏。关键词：加氢反应器弓形格栅有限元变形温度场ABSTRACTIIABSTRACTAimingatcatalystleakageonarchgrilleinthehydrogenationreactorforachemicalplant,thetemperaturefieldanddeformationof321stainlesssteelarchgrilleinhydrogenationreactorunderoperatingtemperatureandoverheatconditionsweresimulatedusingANSYSsoftware.Three-dimensionalsolidmodelwasestablishedaccordingtotheactualarchgrillesize,andthearchgrillewascalculatedbysequentialcouplingmethod.Athightemperatures,thetemperatureongrilleisuneven,andthemaximumtemperaturedifferenceisabout70-80℃Duetooverallthermalexpansionofgrille,grillecausesgreaterinternalstress.Themaximumcompressivestressesonsymmetricalsurfaceat390℃and486℃conditionsare-140MPaand-200MPa.Itchangestoatensilestressofabout250MPawhencoolingtoambienttemperature.Thelowergrillemaximumgapis2.64mmunder390℃atthebottomoftwoarchgrilles.Accordingtotheresults,catalystsdonotleak.Thelowergrillemaximumgapis4.58mmunder486℃atthebottomoftwoarchgrilles.Accordingtotheresults,catalystsdonotstillleak.However，ifthereismorethan2mmgapbetweentwoarchgrilles,thegapbetweentwoarchgrilleswillreaches6.58mmandcatalystswillleak.Keywords:hydrogenationreactor;arcuategrid;finiteelement;deformation;temperaturefield南京工业大学本科生毕业设计（论文）III目录摘要.................................................................................................................IABSTRACT..........................................................................................................II第一章绪论.........................................................................................................11.1课题研究的意义及背景...................................................................................................11.2加氢反应器的发展概况...................................................................................................11.3热应力研究存在问题.......................................................................................................31.4课题研究内容及技术路线...............................................................................................3第二章弓形格栅泄漏原因初步分析...................................................................52.1情况简介...........................................................................................................................52.2检查情况...........................................................................................................................52.3催化剂泄漏部位...............................................................................................................82.4催化剂泄漏堆积过程.....................................................................................................102.5弓形格栅板之间间隙形成的原因.................................................................................102.6冷氢弓形格栅板尖端间隙形成的原因.........................................................................112.7催化剂泄漏的主要原因.................................................................................................11第三章数值模拟及分析.....................................................................................133.1基本假设.........................................................................................................................133.2实体模型.........................................................................................................................133.3材料物性.........................................................................................................................153.4初始条件和边界条件.....................................................................................................153.5模拟计算.........................................................................................................................163.6温度场计算结果分析.....................................................................................................163.6.1操作温度390℃温度场........................................................................................163.6.2温度486℃温度场................................................................................................203.7应力场与变形分析.........................................................................................................223.7.1390℃条件下应力及位移分析..............................................................................223.7.2486℃条件下应力及位移分析..............................................................................27目录IV第四章结论........................................................................................................33参考文献..............................................................................................................34致谢.........