|Kim, Jung woo|
Submitted to: Transport in Porous Media
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/18/2011
Publication Date: 10/1/2011
Citation: Kim, J., Heechul, C., Perfect, E., Pachepsky, Y.A., Sukop, M. 2011. Geometric and Hydrodynamic Characteristics of Three-dimensional Saturated Prefractal Porous Media Determined with Lattice Boltzmann Modeling. Transport in Porous Media. 90:831-846. Interpretive Summary: Modeling water flow and pollutant transport in soils and other natural porous media is an essential component of pollution risk assessment and best management practice selection. Hydraulic parameters of flow and transport models can be measured in controlled experiments, but this is time and labor consuming, and often impractical in large scale projects. The alternative to actually measuring these parameters is to estimate them from more easily obtainable soil properties. We researched the feasibility of estimating hydraulic parameters using fractal models that estimate pore space; fractal models use geometric techniques to realistically mimic pore structures of soils. Fractal pore structures were computer-generated, and flow and transport in these structures were simulated from first principles using the novel powerful lattice Boltzmann simulation technique. We found that hydraulic parameters (such as permeability and solute dispersion coefficient) were reasonably correlated with geometric parameters (such as porosity, effective porosity, and fractal dimension). These results are important for pollution prediction and mitigation in that the work has identified the opportunity to use novel modeling and simulation techniques to characterize pore structure and to estimate flow and transport parameters in soils and other natural porous media.
Technical Abstract: Fractal and prefractal geometric models have substantial potential of contributing to the analysis of flow and transport in porous media such as soils and reservoir rocks. In this study, geometric and hydrodynamic parameters of saturated 3D mass and pore-solid prefractal porous media were characterized using the lattice Boltzmann model. The percolation thresholds of 3D prefractal porous media were inversely correlated with the fraction of micro-pore clusters and estimated as 0.36 and 0.30 for mass and pore-solid prefractal porous media, respectively. The intrinsic permeability and the dispersion coefficient of the 3D pore-solid prefractal were larger than those of 3D mass prefractal, presumably because of the larger solid and pore cluster sizes occurring in 3D pore-solid prefractal. Hydrodynamic parameters, such as intrinsic permeability and dispersion coefficient, were relatively highly correlated with geometric parameters, such as porosity, effective porosity, and fractal dimension (the minimum correlation coefficient = 0.78). However, the multiple regressions including porosity and each of other geometric parameters, such as effective porosity, fractal dimension, and normalized lacunarity, did not significantly improve the accuracy of hydrodynamic parameter estimations. Results of this work showed that the demonstrated applicability of a fractal geometric model to a porous media can result in reasonable estimates of its hydrodynamic parameters.