埋天然气管道泄漏扩散规律研究
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Diffusion of natural gas in layered fill soil is mainly related to the nature of the fill land, that is, porosity, saturation, pressure and other characteristics. There is a delay at the material interface, and the diffusion curve has an obvious inflection point.
In this experiment, the multiphysics field of Darcy ’s law and the transfer of dilute substances iblished by comsol software, and the model of leakage and diffusion of buried natural gas pipelines was constructed. By adjusting different parameter variables, the following conclusions were obtained: With the density of soil particles arranged, as this value increases, the soil texture becomes loose, thereby accelerating the rate of natural gas leakage and diffusion.
随着埋地深度的增加，土壤堆积密度增加，背压增高，天然气扩散阻力增加且扩散至土壤表面距离增加，致使天然气扩散速度降低。
分层填筑土壤中天燃气扩散情况主要与填筑土地性质有关，即孔隙率，饱和度，压力等特点，在材质交界处存在延迟，扩散曲线有明显拐点。
不同情况下都在泄漏口垂直上面土壤表面最快达到警报浓度和爆炸下限，但时间各有所差别。
本实验通过comsol软件建立达西定律和多孔介质稀物质传递耦合的多物理场，构建天然气埋地管道泄漏扩散模型，通过调整不同参数变量得到如下结论：
孔隙率反应着土壤颗粒排列的密集程度，随着该数值提高，土壤质地变得疏松，从而加快了天然气的泄漏扩散速度。
饱和度即土壤中含水量的程度，随着含水量提升，天然气分子在扩散中增加了与水分子的碰撞，使其摩擦阻力提升，因此天然气扩散系数减小，导致天然气扩散速度减小。
Saturation is the degree of water content in the soil. With the increase of water content, natural gas molecules increase the collision with water molecules during diffusion, so that their frictional resistance increases, so the natural gas diffusion coefficient decreases, resulting in the natural gas diffusion rate Decrease.
摘要
随着时代的发展，我国已建立起了密集的天然气管道网格系统，以应对人们日常的生活需求。但因多种因素造成天然气管道破裂，从而引发的泄漏导致的安全事故同时也日益增多。为此利用comsol软件对埋地天然气管道泄漏在土壤中的扩散情况进行模拟，探明各条件对扩散的影响，得到不同条件下地表最先达到一级警报浓度和爆炸下限的时间和位置，为布设合理检测点提供建议。
关键词：天然气，埋地扩散，多孔介质，孔隙率，小孔泄漏
Studyon the Law of Buried Natural Gas Leakage and Diffusion
Abstract
With the development of the times, China has established a dense natural gas pipeline grid system to meet people's daily life needs. However, due to various factors causing the natural gas pipeline to rupture, the number of safety accidents caused by leaks is also increasing. To this end, the comsol software was used to simulate the diffusion of the buried natural gas pipeline leakage in the soil, to explore the effects of various conditions on the diffusion, and to obtain the time and location where the ground surface first reached the first-level alarm concentration and the lower explosion limit under different conditions. Provide reasonable inspection points to provide advice.
With the increase of the buried depth, the soil bulk density increases, the back pressure increases, the natural gas diffusion resistance increases and the diffusion distance to the soil surface increases, resulting in a decrease in the natural gas diffusion rate.
In this experiment, the multiphysics field of Darcy ’s law and the transfer of dilute substances iblished by comsol software, and the model of leakage and diffusion of buried natural gas pipelines was constructed. By adjusting different parameter variables, the following conclusions were obtained: With the density of soil particles arranged, as this value increases, the soil texture becomes loose, thereby accelerating the rate of natural gas leakage and diffusion.
随着埋地深度的增加，土壤堆积密度增加，背压增高，天然气扩散阻力增加且扩散至土壤表面距离增加，致使天然气扩散速度降低。
分层填筑土壤中天燃气扩散情况主要与填筑土地性质有关，即孔隙率，饱和度，压力等特点，在材质交界处存在延迟，扩散曲线有明显拐点。
不同情况下都在泄漏口垂直上面土壤表面最快达到警报浓度和爆炸下限，但时间各有所差别。
本实验通过comsol软件建立达西定律和多孔介质稀物质传递耦合的多物理场，构建天然气埋地管道泄漏扩散模型，通过调整不同参数变量得到如下结论：
孔隙率反应着土壤颗粒排列的密集程度，随着该数值提高，土壤质地变得疏松，从而加快了天然气的泄漏扩散速度。
饱和度即土壤中含水量的程度，随着含水量提升，天然气分子在扩散中增加了与水分子的碰撞，使其摩擦阻力提升，因此天然气扩散系数减小，导致天然气扩散速度减小。
Saturation is the degree of water content in the soil. With the increase of water content, natural gas molecules increase the collision with water molecules during diffusion, so that their frictional resistance increases, so the natural gas diffusion coefficient decreases, resulting in the natural gas diffusion rate Decrease.
摘要
随着时代的发展，我国已建立起了密集的天然气管道网格系统，以应对人们日常的生活需求。但因多种因素造成天然气管道破裂，从而引发的泄漏导致的安全事故同时也日益增多。为此利用comsol软件对埋地天然气管道泄漏在土壤中的扩散情况进行模拟，探明各条件对扩散的影响，得到不同条件下地表最先达到一级警报浓度和爆炸下限的时间和位置，为布设合理检测点提供建议。
关键词：天然气，埋地扩散，多孔介质，孔隙率，小孔泄漏
Studyon the Law of Buried Natural Gas Leakage and Diffusion
Abstract
With the development of the times, China has established a dense natural gas pipeline grid system to meet people's daily life needs. However, due to various factors causing the natural gas pipeline to rupture, the number of safety accidents caused by leaks is also increasing. To this end, the comsol software was used to simulate the diffusion of the buried natural gas pipeline leakage in the soil, to explore the effects of various conditions on the diffusion, and to obtain the time and location where the ground surface first reached the first-level alarm concentration and the lower explosion limit under different conditions. Provide reasonable inspection points to provide advice.
With the increase of the buried depth, the soil bulk density increases, the back pressure increases, the natural gas diffusion resistance increases and the diffusion distance to the soil surface increases, resulting in a decrease in the natural gas diffusion rate.