Computation And Analysis Of CNG Vehicle High Pressure Pipe Flow Field Characteristic And Optimization Design Of Arrangement

The whole 3-D high pressure pipeline of CNG(Compressed Natural Gas)bus is stimulated and analyzed by using the CFD(Computational Fluid Dynamics)theory in this dissertation.After the stimulation and analysis of the whole 3-D high pressure pipeline with different outlet pressure,radius of elbow and when the diameter of pipeline has changed,then draw a conclusion which is in favor of the flow field distribution. This dissertation is consisted of some researches as given bellow:First of all,the research background and research significance are introduced,then function of high pressure pipeline in CNG vehicle,and make detailed description of structure and working process of the high pressure pipeline in a CNG bus.Subsequently, base on the high pressure pipeline structure,three-dimensional model is established.According to the work condition of the high pressure pipeline,internal flow field model is built up,then the model is meshed by Gambit,and the boundary conditions of the grided model are setted up.In the middle of the dissertation,numerical simulation equation and the theory of computational fluid dynamics(CFD) are introduced,which are required during the numerical calculation.Then meke description of the software Fluent,using instructions and the relevant setting of parameters in Fluent are introduced.In the fourth chapter,the dissertation makes analysis of some improvement programs of elbow redius of pipeline,and ensure the optimal one.And compare the pressure and velocity distribution when the elbow of pipeline has changed,and get a better distribution after improvement.In the fifth chapter,through theory caculation can find when the diameter of pipeline become larger,the filling efficiency and gas use ratio of the tank can be increased,through the simulation and analysis of the larger diameter of pipeline modle,it proves the feasibility of the optimization.In the last chapter,the dissertation's conclution has been made and also this dissertation looks into the future of high pressure's research direction.