地埋天然气管道泄漏扩散规律研究.pdfVIP

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。 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。 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。 关键词： 天然气，埋地扩散，多孔介质，孔隙率，小孔泄漏 - I - Study on 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 peoples 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. In this experiment, the multiphysics field of Darcy ’s law and the transfer of dilute substances in porous media was established by comsol software, and the model of leakage and diffusion of buried natural gas pipelines was constructed. By adjusting different paramet