Advective-dispersive transport of dense organic vapors in the unsaturated zone 1
Advective-dispersive transport of dense organic vapors in the unsaturated zone 1
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不饱和区 1 中稠密有机蒸气的平流弥散输运
DOI：
10.1029/wr026i003p00379
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发表时间：
1990
期刊：
影响因子：
11.2
通讯作者：
E. Frind
中科院分区：
文献类型：
--
作者：
C. Mendoza;E. Frind
作为残留物悬浮在非饱和区的有机液体的蒸气可通过充气孔隙迁移相当长的距离，从而造成地下水的广泛污染。为了研究在这些蒸汽的迁移中起作用的各种传输机制，开发了一个数值模型。该模型包括并区分扩散过程、密度梯度引起的平流过程和源处蒸发释放的蒸汽质量引起的平流过程。土壤水分的相分配表示为一个平衡阻滞过程，既减缓羽发展，使污染物可通过渗透水运输。该公式类似于饱和区中密度依赖的输运公式。使用轴对称坐标来表示局部残余饱和溶剂源。三维实验室实验的应用表明，包括密度驱动的平流提供了一个更好的匹配与观测。1，1，1-三氯乙烷蒸气在高渗透性粗砂中迁移的模拟表明，平流可能是一种非常有效的传输机制。
Vapors from organic liquids that are suspended as residual in the unsaturated zone can migrate considerable distances through the aerated pore space and thus cause extensive contamination of the groundwater. In order to investigate the various transport mechanisms that play a role in the migration of these vapors, a numerical model is developed. The model includes and distinguishes between the processes of diffusion, advection due to density gradients, and advection due to the vapor mass released by vaporization at the source. Phase partitioning to the soil moisture is represented as an equilibrium retardation process that both slows plume development and makes contaminants available for transport by infiltrating water. The formulation is analogous to that for density-dependent transport in the saturated zone. Axisymmetric coordinates are used in order to represent localized residual-saturation solvent sources. Application to a three-dimensional laboratory experiment shows that inclusion of density-driven advection provides a better match with the observations. A simulation of the migration of 1,1,1-trichloroethane vapors in a highly permeable coarse sand demonstrates that advection may be a very effective transport mechanism.