Studying the diffusion patterns of natural gas in soil after leakage accidents of buried low-pressure gas pipelines helps in promptly identifying leakage sources,predicting the spread range of leaked gas,and reducing accident losses.This study utilized Design Modeler software to establish a three-dimensional numerical model of the diffusion of methane gas from small holes in buried gas pipelines.Fluent software was employed to numerically simulate the leakage diffusion process of methane gas in soil under different conditions.The effects of pipeline pressure,leakage hole diameter,soil type,soil temperature,and soil moisture content on methane volume fraction and lateral gas diffusion distance were comparatively analyzed.The study revealed a positive correlation between pressure,leakage hole diameter,and soil temperature with methane concentration.Higher pressure,larger leakage hole diameter,and higher soil temperature led to higher methane concentration in the soil within the same leakage duration,resulting in shorter time to reach the explosive lower limit and greater danger.Conversely,higher soil moisture content resulted in lower methane concentration within the same leakage duration.However,under low-pressure conditions,minimal molecular interactions among gas molecules led to higher soil moisture content,resulting in greater lateral gas diffusion distance.Soil type significantly influenced methane diffusion,with gas spreading furthest in sandy soil,posing the highest explosion risk,followed by loamy soil.The viscosity resistance coefficient and inertial resistance coefficient of clayey soil were much smaller than those of sandy and loamy soil,hence,gas concentration was lowest and danger was minimal in clayey soil.The aforementioned research findings provide valuable references for leakage risk assessment and pipeline monitoring and management of buried gas pipelines.
buried pipelinenatural gasleakage and diffusioncomputational fluid dynamicsporous medium
万方数据
维普
