非均质孔隙介质中两相流的光透法应用研究  

A study of the two-phase flow in heterogeneous porous media with the light transmission method

作　　者：乔文静[1] 叶淑君[1] 吴吉春[1] 

机构地区：[1]南京大学地球科学与工程学院/表生地球化学教育部重点实验室,江苏南京210046

出　　处：《水文地质工程地质》2015年第2期112-119,共8页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助(41030746;40872155);国家重点基础研究发展计划(2010CB428803)

摘　　要：地下水中非水相液体(Non-aqueous Phase Liquid,NAPL)的流动及其曝气修复技术是典型的两相流问题。基于实际地下水含水介质的普遍非均质性,本文应用光透法对非均质孔隙介质中两相流进行了定量试验研究,设计了两组砂箱实验,研究气体和重非水相液体(DNAPL)在非均质孔隙介质中的迁移规律,应用了水/气两相和水/NAPL两相饱和度计算模型。实验结果表明:气体主要由不规则通道向上运动,遇到低渗透性透镜体时在其下方堆积,并开始横向运动,绕过透镜体后继续向上运动,最终在砂箱顶部形成连续气体分布,注气速度越大,气体运移范围越宽;DNAPL在自身重力作用下克服毛管压力向下迁移至低渗透性透镜体,DNAPL无法克服该介质的毛管压力,停止垂向入渗,并在其表面堆积,开始横向运移,绕过透镜体后继续向下运动,最终在砂箱底部形成连续DNAPL污染池。均质介质中建立的计算流体饱和度的水/气模型及水/NAPL模型与实验结果较吻合,可用于非均质多孔介质中水/气相和水/NAPL相饱和度的计算。The migration of non-aqueous phase liquid （NAPL） in groundwater and the air spariging technique applied to remove NAPL in aquifer systems are typically a two-phase flow problem. Because of the heterogeneous features of the natural aquifer, two 2-D sandboxes are set up to study the migration of gas and DNAPL in heterogeneous porous media based on the light transmission method and the application of the method to a two- phase flow. Model D for water/gas system developed and Model NW-A for water/NAPL system are applied for the calculation of fluid saturation in the two experiments, respectively. The gas injection experiments show that the gas moves upward in the irregular channels, piling up beneath the low permeability lenses and starting lateral movement. Bypassing the lenses, the gas moves upward again and finally forms continuous distribution on top of the sandbox. It is found that the faster of the gas injects, the wider of the gas migration will be. The results of the DNAPL infiltration experiment shows that TCE mainly moves downward as the influence of its gravity, stopping the vertical infiltration when reaching the low permeability lenses because of its failure to overcome the capillary pressure. The TCE accumulates on the surface and starts transverse motion. Bypassing the lenses, TCE migrates down again and eventually accumulates at the bottom of the sandbox. The two models of quantification of fluid saturations for water/gas system and water/NAPL system developed in homogenous porous media give comparatively consistent results to the observations and can be used to quantify fluid saturations in heterogeneous porous media.

关 键 词：非均质孔隙介质 重非水相液体 气体 饱和度 光透法 模型应用 

分 类 号：X131.2[环境科学与工程—环境科学]