层状非均质多孔介质中LNAPLs污染物运移与分布的锋面扩展模型

通过建立二维物理模型,研究非饱和层状非均质多孔介质中轻非水相液体LNAPLs(Light Non-a-queous Phase Liquids)的入渗机制与变化特征,建立LNAPLs运移与分布的锋面扩展模型,探讨入渗阶段油流锋面扩展速率的变化规律。结果发现:模型中砂土的渗透系数、孔隙度及油的相对渗透系数对LNAPLs运移的锋面扩展速率影响较大,而油的饱和度与压头变化对其影响较小。当LNAPLs由中砂进入细砂与细砂倾斜透镜体时,砂的渗透系数、孔隙度及油的相对渗透系数减小,这种介质结构面的突变改变了LNAPLs锋面扩展速率,其在中砂中锋面扩展速率快而在细砂与细砂倾斜透镜体中锋面扩展速率慢。此外,当LNAPLs进入干湿界面后,由于毛细作用的增强与含水量的加大,其横向比垂向运移的平均锋面扩展速率大。

Infiltration & Distribution front Spreading Model of LNAPLs in Layered Heterogenious Porous Media

The paper is based on a 2-D physical model,the purpose is to explore characteristics of LNAPLs infiltration in unsaturated layered heterogeneous porous media,and establish the inflitration and distribution of LNAPLs front spreading model,forecast the characteristic ratio of oil spreading rate in infiltration stage.The result show that capillary,porosity of sand and relative capillary of oil in model affect LNAPLs front spreading rate,but saturation of oil and the pressure head changed influence is small.When LNAPLs transfer from medium sand to fine,the capillary、porosity of sand and relative capillary of oil,this medium structure of mutation change LNAPLs frontal migration of rate,in the medium sand layered front spreading velocity is quickly and slow in the fine sand layered.In addition,when LNAPLs get to the dry and wet interface,for the capillary of pore water is stronger.