Numerical Analysis Of City Natural Gas Pipeline Leakage Flow Field

With the development of the pressure-gas pipeline industry, naturalgas, liquefied petroleum gas and artificial gas have become the mainsources of energy for urban residents. In the gathering andtransportation process, mechanical damage, corrosion and pipelinenatural factors might lead to gas pipeline leakage. Once gas leakageaccident happen, it will interfere with the natural gas pipeline safeoperation, cause huge economic loss and environmental pollution. Itcan also cause casualties accidents, such as fire, explosion, poisoning.According to the above, it is of great significance to study corrosionleak diffusion process of natural gas pipeline for reducing accidentharm and establishing emergency rescue schemes.Based on the fluid mechanics, the theory of porous media and CFDsoftware, this paper analyzed the diffusion of natural gas when the cityburied pipeline leaked. Firstly, this paper analyzed the factors of leakand diffusion of buried gas pipeline and the jet theory, chose thecalculation method of the buried gas pipeline leak rate. The basicequations of gas flow were given. The theory of porous media, gasdiffusion equations etc. were elaborated. Secondly，the math model andphysics model of natural gas diffusion in atmosphere and soil wereestablished. Finally, basedon the above models, Computational FluidDynamics simulation software was used to simulate the methane leakand diffusion flow field of the city buried gas pipeline. Differentoperation pressure, different diameter of leak hole, different leakagelocation and different environmental temperature were considered toanalyze the methane leak and diffusion flow field. According to thediffusion images of natural gas in the soil and air, the damage concentration range and explosion concentration range of methane weredetermined. And the distribution of natural gas under various workingout was summarized. The analysis of natural gas leak accidents canprovide an idea for these accidents research, whose results and laws willhave certain reference value for the actual emergency rescue program.