The Research On Virtual Visualization Of Pneumatic Flow Pattern In Pipes

With the development of virtual reality and computer simulation technology, people put more emphasis on virtual visualization of complicated fluid. The virtual visualization technology of fluid belongs to vector dynamic visualization technology, which could be accomplished by dynamic texture, particle system and so on. The technology of dynamic visualization could greatly improve the ability of people with regard to the structure of space vector field and the evolvement rules of physics phenomena. The field of materials conveyed by pneumatic pipes is one of the solid -gas two -phase flows, which are complicated fields. To construct the practical mathematics model of pneumatic visualized flow pattern will prompt the improvement of theory of solid - gas two- phases flow and assist the computer design of pneumatic system. It is believed that the virtual visualization of pneumatic system will become an important content of pneumatic researches gradually.The dissertation is based on the research of dynamic visualization and the model of non-regular objects. From the design parameters of pneumatic flow pattern, it extracts the main factors influencing the visualization, such as velocity, the character of materials and the ratio of solid to gas, and considers these as the parameters of visualized system. In this dissertation, the virtual visualization of pneumatic flow pattern is recognized as the dynamic visualization of non-regular objects.The virtual visualization of flow pattern is achieved by particle system, which is a main method of dynamic visualization based on physics. Through the analysis of possibility of applying particle theory to pneumatic virtual visualization, the dissertation provides the visualization process of particle system for flow pattern, the attributes of the material particle and the main interfaces of particle system based on object -oriented analysis and design.According to the requirement of virtual visualization system, the dissertation mainly focuses on the numeric simulation technology, points the problems of arithmetic stability and truncation error and provides some actual scheme. On another aspect, because of the collision detection and response between particle and particle or particle and pipes during the conveying process, the dissertation gives the detection arithmetic based on ray-tracing and checks up the equation of elastic collision based on conversation of energy and inelastic collision based on momentum and coefficient of restitution.Finally, according to the extraction of parameters, the design of object-oriented particle system and collision detection and response, the dissertation builds the virtual visualization prototype system of pneumatic flow pattern on PC with the tools of VC++6.0 and OpenGL. The scheme also designs the visualized interface and human-computer interactive processing. The design achieves the regulation of parameters and the interaction between human and computer and proves the feasibility of virtual visualization flow pattern scheme based on particle system.