| CAD is one of the most prominent engineering technology productions in the 20th century , which is an new key technology in alternation of traditional industry and promotion of national economy by means of top and new technology. Heat exchangers are used widely in civil , industrial and national defence departments and so on. The developments of high efficiency heat exchangers have important meanings to construction of civil economy. The New Type High Efficient Heat Exchanger(NTHE) is the patent developed by the Thermal Energy Research Center of Zhengzhou University , in order to promote the popularization of the technology, HECAD software system which consists of process design, mechanical design, components design and assembly drawings design of NTHE has been completed by our Research Center. Now , 2D CAD drawing software is very prevalent , but which has many limits in exhibition of 3D objects. With the development of computer 3D graphics technology , designers can express their intensions more directly and thoroughly by 3D body models. Advanced CAD tasks such as checkage of assembly and interference, the analysis by FEM and analysis of movements etc. may be carried on based on 3D models.The subject of this dissertation roots in R&D of CAD/CAE intelligent integration technology of important process equipments which is one of magnitude science and technology projects of Henan province, 3D modeling technology is one of the key research parts of the project. It is an important sector of engineering design, impenetrating core information of engineering design. At the same time, the integrality, abstraction and maneuverability of information have decisive effect on information integration of CIMS. HECAD is a CAD system based on 2D, it expresses 3D components and constructions by projections of different directions, but it is difficult to distinctly exhibit some complicated situations such as deflection fence set. In the course of manufactory and assembly, the difference between new constructions and traditional baffle construction causes some trouble. If there is a 3D simulation of dynamic assembly course, the present problem is able to be solved, what's more, an efficient method by which assembly order of new constructions can be set down will be gained accordingly. In addition, when we research and develop high efficiency and energy-saving heat exchanger, the analysis by FEMwhich aims at betterment and optimization of constructions needs solid models, the analysis of numeric simulation of fluid flow fields and temperature fields of the whole heat exchanger also needs 3D models. Therefore, this dissertation has researched and developed the 3D modeling system of NTHE.Based on summary and analysis of CAD technology, computer graphics, 3D modeling method, development environment and database technology, this dissertation has made researches and practice with the emphasis on the following several aspects:1) The development of 3D modeling technology of CAD experiences wire frame modeling, curved surface modeling, solid modeling, parameterized modeling and variable modeling. The technologies of different period are usually coexistent and not exclusive in concrete software products. Parameterized modeling pays attention to the neighborhood of geometry graphics element, defining and modifying geometric model through constraints, which is fit to the design field characterized completely. Because the special components of NTHE have been normalized , other common components can also be designed according as manual and GB, The 3D modeling system of NTHE adopts parameterized solid modeling.2) Considering widespread extent in our country and facility of AutoCAD , a prior reason is the compatibility and inheritance of between 3D modeling system and HECAD which is accomplished by means of ADSRX and Visual C++ 5.0 , this dissertation selected ObjectARX 2000 and Visual C++ 6.0 based on AutoCAD and 3DS MAX. The 3D solids produced by 3D modeling of AutoCAD system... |
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