Application Research Of City Gas 3D Dynamic Leakage And Diffusion Coupled With CFD And GIS

As is known to all,the issue of city gas pipeline leakage and diffusion has been a hot concern of contemporary society. It is very important to study the law of it. Computational fluid dynamics(CFD) numerical simulation method has been accepted by the domestic and foreign researchers because the advantages of short cycle, low cost, high performance, wide application range and so on. And in recent years,it has made considerable development and progress to improve. A more and more important role as it played in the field of researching and designing of major engineering.The advantage of FLUENT software is the powerful calculating ability of the numerical solution. But it is still relatively weak in modeling function of building multi forms and large-scale buildings. Geographic Information System(GIS) has strong advantage of data storage and processing, graphic display and expression and result analysis. It will be a new exploration of fully appling their advantages to solve the problem of the law of city gas pipeline leakage and diffusion.As the characteristic of complex, numerous, various shapes of the city buildings group. The workload of the traditional method of using CFD in modeling large-scale city buildings is quite heavy and difficulty. Due to the limitation, a fast and efficient modeling method is required to seek and GIS data in geographic information system brings the dawn in order to solve the problem. Due to the current GIS data in China is still in the stage of development and other reasons and based on the inconvenience of obtain direct extraction of relevant data,we have collected form data and other related information of the city buildings in this paper. Firstly,the three-dimensional model of city residential buildings group is established and the real scene is reproduced in ArcGIS, so it can instead of completing the modeling work of CFD and greatly simplifies the workload of modeling of the city gas leakage and diffusion simulation. It also indicates that it is feasible of using GIS data for CFD modeling and the application prospect of it is quite wide.The model file of city buildings which built in GIS has successful imported to the grid division software of CFD and middle software of AutoCAD has been applied to transform it. Combining with the physical model and numerical model which have been established before and based on unsteady state leak and diffusion model,then taking account of the influence of different conditions of city gas leakage diffusion,3D dynamic simulation of leakage and diffusion of city gas by using ANSYS software and got related conclusions.How to realize CFD and GIS coupling is the very difficulty point in this paper.Firstly,we should transformate the datas which FLUENT simulated,unified the data format and the three-dimensional coordinate system has become the key to the technology of coupling technology.Secondly,through analyzing problems and solving the problems,input the point group data into GIS and value symbol concentration of the corresponding coordinate points,then makes the FLUENT simulation results have been reproduced in GIS successully.we aimed at explore a new method:establishing large scale 3D city buildings group by using GIS data for CFD,then FLUENT software simulates the law of 3D dynamic leakage and diffusion of city gas. It provides a new way of building large scale of city area rapidly and solves the problem of displaying and analyzing the city gas leakage diffusion better.