土壤-大气中燃气泄漏扩散规律研究

Study on diffusion law of leakage gas in soil-atmosphere

为对燃气管道、与其并行管道的敷设及燃气泄漏事故的应急管理决策提供依据,采用环刀法和自主搭建的试验平台,获得孔隙度和土壤阻力系数等土壤扩散控制方程的关键参数;建立埋地管道燃气泄漏的物理模型,并运用计算流体动力学（CFD）三维模拟的方法,研究管道埋深及泄漏孔径对燃气沿土壤-大气扩散规律的影响。结果表明：随着埋深的增加,燃气在土壤中的危险区域范围先减小后增大;随着泄漏孔径的增大,危险区域范围明显增大;燃气沿土壤-大气扩散时易在街谷内形成近地面积聚。因此,敷设燃气管道时适宜的埋深可减小燃气在土壤中扩散的危险区域范围,与燃气管道存在耦合危险的并行管道最好沿街道两边分开敷设,街道空腔区是燃气泄漏事故应急管理的重点区域。

This study intends to provide a more reliable theoretical basis for the laying of gas pipeline,parallel pipeline with gas pipeline and emergency-management decisions following accidental gas leaks.The porosity and the resistance coefficient of soil which are the key parameters of governing equations in soil were obtained by using the cutting ring method and a self-made experimental platform respectively. A physical model was built for leakage of gas from a buried gas pipeline. Effects of buried depth and leakage aperture on diffusion process of leakage gas in soil-atmosphere were investigated using a three-dimensional CFD model. The results show that the area of the dangerous zone in soil decreases first and increases afterwards with the increase of the buried depth,that the area of the dangerous zone increases obviously with the increase of cross-section of leakage aperture,that gas is easy to form accumulation in the ground of the street valley,appropriate buried depth is an important factor to reduce the area of the dangerous zone,that the parallel pipeline having a coupling danger with the existing gas pipeline should be laid along both sides of the street separately and that the cavity of the street is the most crucial area for emergencymanagement following accidental gas leaks.