Simulation Study On Leakage And Diffusion Of Urban Gas Pipeline Based On CFD And GIS

With the acceleration of urbanization process in China and the application acceleration of clean natural gas energy, the scale of city gas network has been expanding. City gas pipelines located in various areas of the city, their own corrosion, natural damages and human activities will cause accidents of the failure of pipelines. It not only affects the stability of the city gas supply, but also causes heavy casualties and huge property losses, so it brings risks to the public security and stability of the city. The study of the diffusion law of gas" leakage in the atmosphere can assist decision-makers formulate scientific and rational contingency plans and take effective measures to the rescue, to improve the safety management of urban public.The diffusion mechanism of gas leakage and diffusion processes in city buildings environment is very complex, for it’s affected by a variety of factors such as building layouts, spatial characteristics and local weather conditions. At the present stage, the research is mainly focused on only one aspect of the study of diffusion mechanism or consequence analysis, so it has a lack of a comprehensive study of the whole diffusion process of the city gas pipeline leak accident. Based on these factors, in this paper we proposed a method. The method integrates the Geographic Information System (GIS) and Computational Fluid Dynamics (CFD), combines the advantages of GIS in building diffusion geometric model and space analysis with the advantages of CFD in the fine simulation of gas diffusion, makes a systematical study in three aspects of theoretical research, diffusion simulation and result analysis.This paper mainly includes the following parts:(1) Research on domestic and foreign literature and information about simulation of gas pipeline leakage and diffusion. It is analyzed existing research results and summarized the methods of gas pipeline leakage and diffusion. It is analyzed the feasibility about city gas pipeline leakage and diffusion of integration of GIS and CFD through theoretical research.(2) It proposed a method about city gas pipeline leakage and diffusion simulation of loose integration based on CFD and GIS. The integration scheme, work flow and data transfer mode of GIS and CFD are determined. And it realized by programming calculation of the complex gas pipeline leakage source and node data preprocessing.(3) It was combined with the data of specific case to calculate using proposed method of city gas pipeline leakage and diffusion simulation based on CFD and GIS and explored the law of the influence of diffusion time, wind direction, wind speed, ground condition and other factors on the diffusion of natural gas. Especially in view of the characteristics of dense urban buildings, it was analyzed the diffusion law about four kinds of area of multi-story buildings, high-rise buildings and square.It was achieved the combination of numerical simulation and spatial analysis function and improved the scientific nature and accuracy of gas leakage and diffusion simulation through research on CFD and loose GIS integration method. At same time, it was provided a new way of thinking and reference of city gas pipeline leakage and diffusion simulation research.