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外文原文Computer-aided design of floating head heat exchanger based on UG software1 introductionThe EDS of Unigraphics (UG) software is currently the worlds most advanced integrated CAD/CAM/CAE of high-end software, widely used in aerospace, automobile, shipbuilding, general machinery and consumer electronics and other industrial fields.UG software is nowadays many of the worlds leading industrial product designer and manufacturer for concept design, industrial design, mechanical structure design and engineering simulation, digital manufacture technology .In China, the UG software has with Pro/E software to become the most popular with the users and the general acceptance of the three-dimensional parametric design software, for the popularization and improvement of Chinas manufacturing CAD technology has played a positive and significant effect .But in the current domestic users, most designers only use CAD and CAM module of UG software, the CAE module is rusty, and domestic information about UG and books to introduce CAE are few.In the developing of computer and CAD technology in modern times, the finite element analysis method will get more and more widely in engineering design and analysis, finite element analysis software and the integrated application of CAD system is to make the design level happen a qualitative leap, it can increase the reliability of the products and engineering, many conventional calculation doesnt give a analysis of the data, before the product manufacturing or engineering construction found potential problems in advance.2main components of floating head heat exchanger CAD2.1 parts modelingUG solid Modeling module (Modeling) USES the compound Modeling technology, the parameter design and characteristics of geometric design method combining Modeling.Mainly has the entity modeling, wire frame modeling, free-form surface modeling, etc. Three 4.Specific use what kind of modeling method, according to the characteristics of the object, we usually use mainly entity modeling.In entity parts model, can use basic voxel to establish a simple entity, can also be based on the curve to establish various scanning, sketches the stretching, rotating entity, can also use the system to provide features to create a variety of body.For a component model, although there is no a fixed sequence modeling and modeling methods, but still have certain rules to follow.Generally should be according to the structure characteristics of the components, to set up a basic voxel or scanning features, and then gradually create parts of holes, slotting, cavity, convex sets, convex pad and user defined features, finally to create roundingoff, chamfering, thread, pruning and arrays.According to the basic principle of floating head of floating-head type heat exchanger tube plate, saddle, tube box, shell and tube bundle main components such as 3 d modelling, model is intuitive, as shown in figure 1-5.2.2 parts and componentsUG assembly module (Assemblies) using a pointer assembly parts rather than copy parts to realize virtual assembly 5, can reduce the memory requirements of assembly, check the assembly model in time if there is a design size of interference, the smooth progress of the actual assembly model for the future provide a reliable guarantee.Assembly information can be easily caused by the draw assembly drawings, and can quickly generate assembly diagram, save map assembly drawing and parts of time and cost.When change of assembly of parts, assembly will be automatically updated.Figure 6 to use the corresponding matching relationship of floating head heat exchanger assembly drawing, and transparent way outside shell shows the internal form of floating head heat exchanger assembly relation, the whole body of the heat exchanger is more intuitive.2.3 to generate two-dimensional engineering graphicsUG engineering drawing module (Drafting) can be easily with the entity model coordinated two-dimensional engineering graphics.When the entity model changes, the size of the engineering drawing sync automatically updates, reduce model change time needed for two-dimensional chart updates, fundamentally put an end to the traditional size contradictions in the design of two-dimensional engineering graphics, throw line, such as common errors, so as to ensure the correct of two-dimensional engineering graphics.Based on the floating head heat exchanger tube plate, for example by adding a master model view, projection views and local amplification figure views such as establishing two-dimensional engineering graphics, figure 7 is according to our country perfect tube plate drawing standards to modify the default drawing parameters of two-dimensional engineering graphics. 3 CAE implementation of floating head heat exchangerCAE analysis module of UG (Scenario) using the worlds most advanced calculator, such as the MSC/NASTRAN, MSC/PATRAN and MDI/were ADAMS, MOLDFLOW, etc.UG to the first-class software are not simply integration, but implant to it, do the consistency of the user interface, and according to the need to expand the corresponding function.3.1 the installation process of floating head heat exchanger and the medium flow simulationMotion simulation is the main part of UG/CAE to, it can be on any 2 d or 3 d institutions complex kinematics simulation analysis, dynamic analysis and design.Through the above of floating head heat exchanger of the three-dimensional entity model is set up, using UG Scenario For the function of the Motion to the three-dimensional solid model of floating head heat exchanger need movement components are given in the kinematics characteristic of a certain to set up certain connections between the parts, thus the Motion of floating head heat exchanger is established the simulation model, and output the corresponding animation.The entire model are verified by simulation movement assembly and the rationality of the design of motion mechanism.The floating head heat exchanger structure and installation process more intuitive, more image, vivid internal medium flow.3.2 the finite element analysis of the saddleThe Scenario of UG for Structures is an integrated CAE tools.When concrete analysis part structure, the module will automatically with the parts of the structure of the network partitioning, boundary constraint and load condition changes correspondingly change, which the new results are obtained.So repeatedly, can be more easily scheme analysis, choose the optimal solution.Upon confirmation of scheme, digital model of CAD module will automatically change to get the best design model.In the floating head heat exchanger, saddle is used to support the horizontal heat exchanger 6, the design requirements and the saddle should have sufficient strength and resistance to deformation ability.This paper simulated the saddle by heat exchanger of the effect of gravity stress, the stress is displayed through the clouds, the size of the force function and is accompanied by the saddle and the deformation.3.2.1 import master model and set the parametersImport figure 2 saddle as the main model, into the structure analysis module.Saddle material is Q235A, elastic modulus E = 220 x 109 pa, poissons ratio u = 0.3, density of rho = 7.85 x 10-6 kg/mm3.Material properties as shown in the table 1.3.2.2 applied load and constraintsPressure on the saddle here only consider heat exchanger, the heat exchanger and the total weight of the fluid W / 2 = 50000 n, with the circular arc of the bearing load ACTS on the saddle surface, as shown in figure 8, since the role of the saddle by anchor bolt, with anchor bolt is fixed on the ground.Symmetry constraint in the bolt hole, at the hem of vertical displacement constraints.As shown in figure 9.3.2.3The finite element grid was divided Meshing was done for the whole model, the use of smart grid, such a finer division of grid, the results of the analysis more accurate, this paper choose the UG software bring UGVM network generator four nodes tetrahedron three-dimensional grid, mesh of finite element model is shown in figure 10. 3.2.4 solving and result outputPrior to calculation, the finite element model for a check to see whether setting error, the system will provide a inspection report, can be set according to the report of some unreasonable, modified the calculation is reasonable, no error message.Output saddle seat move diagram (see figure 11) and stress diagram (see figure 12), figure 11 shows the saddle on the Z axis direction due to the pressure of the heat exchanger and the displacement in the Z axis.Can consider when processing between two straight floor with two support bar, to strengthen the resistance to deformation ability of the saddle.Figure 12 shows the saddle load cases, the two straight floor produces large stress, and on the floor with spot welding with gasket stress concentration.Other local stress distribution is more homogeneous.Therefore, we in the machining process of the saddle to improve the quality of the weld on select material is available in the separation of high strength material. 4 conclusionCreate of floating head heat exchanger using UG 3 d model of the parts and image, vivid, intuitive reflect the structure of floating head heat exchanger;Using UG to the strength analysis of some parts effectively improves the reliability of these parts;Production of three-dimensional dynamic simulation for engineering and technical personnel to master the structure and working principle of floating head heat exchanger;For producers and installers save analysis time, improve the production efficiency at the same time.Visible, along with the development of the computer aided technology and computer network technology, the heat exchanger will realize from the design, manufacturing to sales and maintenance of computer and information technology.With the aid of the powerful features of the computer aided technology, can realize the optimal design of heat exchanger, greatly improve the reliability of heat exchanger, at the same time with the aid of computer network technology, can realize resource sharing in the whole industry, improve the efficiency of heat exchanger design, manufacture, save a lot of production cost and create greater economic benefits for the enterprise.译文基于UG软件的浮头式换热器计算机辅助设计1 前言 美国EDS公司推出的Unigraphics(简称UG)软件是当前世界上最先进的集成CAD/CAM/CAE的高端软件，广泛应用于航空航天、汽车、造船、通用机械和消费电子产品等工业领域。UG软件被当今许多世界领先的工业产品设计商与制造商用来从事概念设计、工业设计、机械结构设计以及工程仿真、数字化制造等各个技术领域。在中国，软件已经和Pro/等软件一起成为最受用户欢迎和普遍接受的三维参数化设计软件，为中国制造业CAD技术的普及和提高起到了积极显著的作用。但就目前国内用户而言，大多数设计者只使用UG软件中的CAD和CAM模块，对CAE模块比较生疏，而国内关于的资料与书籍对CAE也很少有介绍。在计算机和CAD技术大力发展的当今时代，有限元分析方法在工程设计和分析中将得到越来越广泛的重视，有限元分析软件与CAD系统的集成应用使设计水平发生了质的飞跃，它能增加产品和工程的可靠性，得到许多常规计算无法得出的分析数据，在产品制造或工程施工前预先发现潜在的问题。2 浮头式换热器的主要零部件CAD实现2.1 零件建模 UG实体建模模块(Modeling)采用复合建模技术，将参数设计和特征几何设计等方法结合起来建模。主要有实体建模、线框建模、自由曲面建模等3种4。具体用哪一种建模方法，要依据对象的特点而定，我们通常用到的主要是实体建模。在建立实体零件模型时，既可以用基本体素建立简单的实体，也可以通过对曲线、草图的拉伸、旋转建立各种扫描实体，还可以用系统提供的特征创建各种特征体。对于一个零件模型，虽然没有一种固定的建模顺序和建模方法，但是还是有一定规律可循的。一般应根据零部件的结构特点，先建立一个基本体素或扫描特征，再逐步创建零件的孔、键槽、型腔、凸台、凸垫及用户定义等特征，最后创建倒圆、倒角、螺纹、修剪和阵列等特征。按照上述基本原则对浮头式换热器浮头管板、鞍座、管箱、筒体及管束等主要零部件进行三维造型，模型真实直观，如图1-5所示。2.2零部件装配 UG装配模块(Assemblies)使用指针装配零件而不是拷贝零件实现虚拟装配5，可以使装配的内存需求减少，及时检查装配模型是否存在设计尺寸干涉，为将来实际装配模型的顺利进行提供可靠保证。由此所产生的装配信息可以方便地绘制装配图，并能快速生成装配分解图，节省绘制装配图和零件图的时间和成本。当组成装配的零件有所改变时，装配会自动更新。图6为运用相应的配对关系建立的浮头式换热器装配图，并以外壳体透明的方式展示了浮头式换热器内部组建的装配关系，使换热器的整体机构更加真实直观。 2.3二维工程图生成 UG工程制图模块(Drafting)可以方便地得到与实体模型协调一致的二维工程图。当实体模型改变时，工程图尺寸会同步自动更新，减少因模型改变二维图更新所需时间，从根本上杜绝传统的二维工程图设计中尺寸矛盾、丢线等常见错误，从而保证二维工程图的正确无误。本文以浮头式换热器管板为例通过添加主模型视图，投影视图及局域放大图等视图建立二维工程图，图7为按照我国制图标准修改缺省图纸参数完善的管板的二维工程图。3 浮头式换热器的CAE实现 UG的CAE分析模块(Scenario)采用世界上最先进的计算器，如MSC/NASTRAN、MSC/PATRAN、MDI/ADAMS、MOLDFLOW等。UG对这些一流的软件并不是简单地集成，而是“植入”到其中，做到用户界面的一致性，并根据需要扩充相应的功能。3.1浮头式换热器的安装过程及介质流动仿真 运动仿真是UG/CAE模块中的主要部分，它能对任何二维或三维机构进行复杂的运动学分析、动力分析和设计仿真。通过以上建立的浮头式换热器的三维实体模型，利用UG的Scenario For Motion的功能给浮头式换热器的三维实体模型中的需要运动的部件赋予一定的运动学特性，再在各个部件之间设立一定的连接关系，从而建立浮头式换热器的运动仿真模型，并输出相应的动画。通过运动仿真检验了整个模型装配及运动机构设计的合理性。使浮头式换热器结构及安装过程更直观、内部介质流动更加形象、逼真。3.2鞍座的有限元分析 UG的Scenario for Structures是一个集成的CAE工具。在具体分析零件结构时，该模块会自动随零件结构的网络划分、边界约束、载荷工况发生的变化作相应的变化，从而得出新的结果。这样反复多次，可很方便地进行多方案的分析，从中选出最优的方案。方案一经确认，CAD模块的数字模型也会自动地改变，从而得到最佳的设计模型。在浮头式换热器中，鞍座是用来支撑卧式换热器的6，设计要求鞍座要有足够的强度和抗变形能力。本文模拟鞍座受换热器的重力的作用而产生的应力，该应力的大小是通过云图显示出来的，并伴随有鞍座受力作用而产生的变形。3.2.1 导入主模型并设置参数 导入图2鞍座作为主模型，进入结构分析模块。鞍座材料为Q235A，弹性模量E=220109Pa，泊松比=0.3，密度=7.8510-6 kg/mm3。材料特性详见表1。3.2.2 施加载荷与约束 在这里只考虑换热器对鞍座的压力，即换热器与流体的总重量W/2=50000N，以轴承载荷作用于鞍座的圆弧面上，如图8所示，因为鞍座受地脚螺栓的作用，以地脚螺栓固定在地面上。在螺栓孔处产生对称约束，在底边上产生竖直方向的位移约束。如图9所示。 3.2.3 划分有限元网格对整个模型进行网格划分，使用智能网格划分，这样划分出来的网格更细，分析的结果更精确，本文选择UG软件自带的UGVM网络生成器生成四节点四面体三维立体网格，划分网格后的有限元模型如图10所示。3.2.4 求解及结果输出在进行计算之前，对有限元模型进行一次检查是否设置错误，系统会提供一份检查报告，可以根据报告对一些不合理的设置进行修改，本次计算合理，无错误信息。输出鞍座位移图（详见图11）和应力图（详见图12），图11说明鞍座在Z轴方向上因受换热器的压力而产生的在Z轴方向上的位移。在加工时可以考虑在两直肋板间加上两根支撑杆，以加强鞍座的抗变形能力。图12说明鞍座负重情况下，在两直肋板产生较大应力，且在肋板与垫片的焊接处有应力集中情况发生。其它地方应力分布较均匀。故此，我们在鞍座的加工过程中要提高焊缝的质量，选材上可在这部分选强度高的材料。4 结论用UG创建的浮头式换热器零部件的三维模型，形象、逼真，非常直观的反映了浮头式换热器构造；运用UG对部分零部件进行的强度分析有效地的提高了这些零部件可靠性；制作的三维动态模拟能够方便广大工程技术人员掌握浮头式换热器的结构与工作原理；为生产者以及安装者节省了分析时间，同时提高了生产效率。可见，随着计算机辅助技术和计算机网络技术的发展，换热器将实现从设计、制造到销售、维护的计算计化与信息化。借助计算机辅助技术的强大功能，完全可以实现换热器的最优化设计，大大提高换热器的可靠性，同时借助计算机网络技术，可以实现在全行业内的资源共享，提高换热器设计、制造的效率，节约大量的生产成本，为企业创造更大的经济效益。
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