Comparison of modeling methods for the determination of effective porosities and diffusion coefficients in through‐diffusion tests
Comparison of modeling methods for the determination of effective porosities and diffusion coefficients in through‐diffusion tests
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穿透扩散试验中确定有效孔隙率和扩散系数的建模方法比较
DOI：
10.1029/2008wr007236
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
D. Barnes
中科院分区：
文献类型：
--
作者：
J. Benning;D. Barnes
扩散系数和有效的，或运输，孔隙度是重要的参数，在评估的命运和运输的污染物在破碎的岩石系统，当污染物的运输需要考虑在低到可以忽略不计的平流区。本研究提出并讨论了各种解决方案，分析和半分析，菲克定律的典型的通过扩散实验，并将这些解决方案的三个通过扩散实验数据集的结果。对两个天然角砾岩样品（体积测量孔隙率约为13.7%和16.8%）和一个制造的多孔板样品（体积测量孔隙率为40.9%）进行了这些穿透扩散实验，使得样品的扩散率显示出数量级差异。对于每个实验，推导出的有效孔隙率和固有的扩散系数为每种方法进行了比较。结果表明，半解析解提供了一种改进的方法，用于可靠地估计通过扩散实验数据的有效孔隙率;然而，在导出的本征扩散系数中，方法之间的差异很小。
Diffusion coefficients and effective, or transport, porosities are important parameters in the assessment of the fate and transport of contaminants in fractured rock systems and when contaminant transport needs to be considered in zones of low to negligible advective flows. This study presents and discusses various solutions, analytical and semianalytical, to Fick's law for the typical through‐diffusion experiment and applies these solutions to the results of three through‐diffusion experimental data sets. These through‐diffusion experiments were conducted on two natural breccia samples, with bulk measured porosities of approximately 13.7% and 16.8%, and one manufactured porous plate sample with a bulk measured porosity of 40.9%, such that the samples displayed order of magnitude differences in their diffusivities. For each experiment, the derived effective porosities and intrinsic diffusion coefficients for each method are compared. It was shown that the semianalytical solution provides an improved method for reliably estimating the effective porosity from through‐diffusion experimental data; however, there is little difference between methods in the derived intrinsic diffusion coefficients.