不同土壤对输气管道泄漏扩散影响模拟分析

针对埋地输气管道泄漏气体在土壤中的迁移过程，以FLUENT软件为平台，研究了泄漏气体在土壤中的对流扩散规律，得到泄漏后的气体会在管道泄漏口形成椭球形的高浓度区，以浓度差为主要推动力的横向扩散小于以压力差为主要推动力的纵向对流，该结论与全尺度试验结论吻合。以甲烷爆炸下限扩散半径与地面甲烷质量分数的变化为尺度，研究了土壤性质包括土壤孔隙率、土壤含水率、土壤密度对气体对流扩散行为的影响，得出土壤孔隙率才是影响气体对流扩散行为的重要因素。模拟所得结论为埋地管道泄漏风险评估、事故应急疏散、管道设计与施工等提供了参考。

Simulation analysis of the influence of different soil on gas pipeline leakage and diffusion

According to the migration process of the leakage gas in the soil of the buried gas pipeline, the convection and diffusion law of the leakage gas in the soil is studied based on the FLUENT software. It is found that the leakage gas will form an ellipsoid high concentration area in the leakage port of the pipeline, and the transverse diffusion with the concentration difference as the main driving force is less than the longitudinal convection with the pressure difference as the main driving force. This conclusion is consistent with that of full-scale experiment. The effects of soil properties, including soil porosity, soil moisture content and soil density on the behavior of gas convection and diffusion were studied based on the scale of the diffusion radius of the lower explosion limit of methane and the mass fraction of methane on the ground. The simulation results provide a reference for risk assessment, emergency evacuation, pipeline design and construction.