Straining of nonspherical colloids in saturated porous media
Straining of nonspherical colloids in saturated porous media
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DOI：
10.1021/es071328w
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发表时间：
2008-02-01
影响因子：
11.4
通讯作者：
Saiers, James E.
中科院分区：
文献类型：
--
作者：
Xu, Shangping;Liao, Qian;Saiers, James E.
我们探讨了胶体形状对应变动力学的影响，通过测量填充石英砂的饱和柱内的球形和非球形胶体的过滤。我们的观察表明。花生状胶体的输送与直径等于花生状胶体短轴长度的球形胶体的输送相匹配。球形胶体的应变速率与胶体粒径（d（p））与砂粒粒径（d（g））之比（d（p）/d（g））呈线性关系（0.0083 < d（p）/d（g）< 0.06）。该线性关系还量化了花生形颗粒的应变速率，条件是颗粒的短轴长度用于d（p）。孔隙尺度模拟的结果表明，花生形颗粒采用的首选方向，因为它接近孔隙空间收缩，使其主轴往往与当地的流动方向。这种重新取向的程度随着颗粒的纵横比而增加。这项研究的结果表明，应变是敏感的胶体形状的变化，这个过程的动力学可以近似的基础上可测量的性质的非球形胶体和多孔介质。
We explore the effects of colloid shape on straining kinetics by measuring the filtration of spherical and nonspherical colloids within saturated columns packed with quartz sand. Our observations demonstrate. that the transport of peanut-shaped colloids matches the transport of spherical colloids with diameters equal to the minor-axis length of the peanut-shaped colloids. The straining rates of the spherical colloids vary linearly with the ratio of colloid diameter (d(p)) to sand-grain diameter (d(g)) for 0.0083 < d(p)/d(g) < 0.06. This linear relationship also quantifies the straining rates of the peanut-shaped particles provided that the particle's minor axis length is used for d(p). Results of pore-scale simulations reveal that a peanut-shaped particle adopts a preferred orientation as it approaches a pore-space constriction such that its major axis tends to align with the local flow direction. The extent of this reorientation increases with the particle's aspect ratio. Findings from this research suggest that straining is sensitive to changes in colloid shape and that the kinetics of this process can be approximated on the basis of measurable properties of the nonspherical colloids and porous media.