Department of Geology, University of Utah, Salt Lake City, Utah 84112, USA.
Environ Sci Technol. 2009 Nov 15;43(22):8573-9. doi: 10.1021/es901242b.
A "hemispheres-in-cell" geometry is provided for prediction of colloid retention during transport in porous media. This new geometry preserves the utilities provided in the Happel sphere-in-cell geometry; namely, the ability to predict deposition for a range of porosities, and representation of the influence of neighboring collectors on the fluid flow field. The new geometry, which includes grain to grain contact, is justified by the eventual goal of predicting colloid deposition in the presence of energy barriers, which has been shown in previous literature to involve deposition within grain to grain contacts for colloid:collector ratios greater than approximately 0.005. In order to serve as a platform for predicting deposition in the presence of energy barriers, the model must be shown capable of quantitatively predicting deposition in the absence of energy barriers, which is a requirement that was not met by previous grain to grain contact geometries. This paper describes development of the fluid flow field and particle trajectory simulations for the hemispheres-in-cell geometry in the absence of energy barriers, and demonstrates that the resulting simulations compare favorably to existing models and experiments. A correlation equation for predicting collector efficiencies in the hemispheres-in-cell model in the absence of energy barriers was developed via regression of numerical results to dimensionless parameters.
提供了一种“半球壳-壳内颗粒”模型，用于预测胶体在多孔介质中迁移过程中的保留。这种新模型保留了 Happel 球壳-壳内颗粒模型所提供的功能；即，能够预测一系列孔隙率下的沉积，以及相邻收集器对流体流场的影响。这种新模型包含了颗粒间的接触，其合理性最终目标是预测有能量障碍存在时胶体的沉积，这在之前的文献中已经表明，对于胶体：收集器比例大于约 0.005 的情况，胶体沉积发生在颗粒间的接触中。为了成为预测有能量障碍存在时胶体沉积的平台，该模型必须能够定量预测无能量障碍存在时的沉积，而这是之前的颗粒间接触模型所无法满足的要求。本文描述了在无能量障碍的情况下，半球壳-壳内颗粒模型的流场和颗粒轨迹模拟的开发，并证明了所得到的模拟与现有模型和实验结果吻合良好。通过对数值结果进行回归分析得到无量纲参数，开发了一种用于预测无能量障碍情况下半球壳-壳内颗粒模型中收集器效率的相关方程。
