This paper focuses on the perforation-caused leakage diffusion of the underground gas pipeline. Common situations, such as normal leakage model, perforation leakage model and pipe model, are analyzed by theoretical method, and so does the leakage model of natural gas in atmosphere, such as Gauss model. Subsequently, the actual perforation leakage diffusion problem is simplified into an ideal model based on the characteristics of buried gas pipeline. CFD software FLUENT is adopted to perform a transient simulation of this problem, by which the changing trend of the diffusion concentration and velocity of methane with time is obtained and the influence from perforation diameter is further investigated. The results obtained in this paper provide some scientific basis to the safety management and accident rapid rescue of underground gas pipeline.
