Weigand Timothy M, Miller Cass T
Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Phys Rev E. 2020 Sep;102(3-1):033104. doi: 10.1103/PhysRevE.102.033104.
Nondilute transport occurs routinely in porous medium systems. Experimental observations have revealed effects that seemingly depend upon density, viscosity, velocity, and chemical activity. Macroscale models based upon averaged behavior over many pores have been relied upon to describe such systems to date, which require parametrization of important physical phenomena in material coefficients. To advance fundamental understanding of these complex systems, we examine nondilute transport from a fundamental microscale, or pore-scale, continuum modeling perspective. We approximate the solution of a model based upon the variable-density Navier-Stokes equations and a nondilute species transport equation. Known dependencies of the densities, viscosities, chemical activity, and diffusion for a salt solution on chemical composition are included in the model. Microscale model solutions are averaged to the macroscale and compared with extant experimental observations. Investigation of the effects of various physical phenomena on the microscale velocity distribution and the observed macroscale dispersion are considered using dimensional analysis and constrained simulations. Simulation results are used to explain observed experimental results in light of underlying mechanisms. Conditions under which the various physicochemical effects investigated are important are revealed.
非稀释传输在多孔介质系统中经常发生。实验观察揭示了一些似乎取决于密度、粘度、速度和化学活性的效应。迄今为止，基于许多孔隙平均行为的宏观模型一直被用来描述此类系统，这需要在材料系数中对重要的物理现象进行参数化。为了推进对这些复杂系统的基本理解，我们从基本的微观尺度或孔隙尺度连续介质建模角度研究非稀释传输。我们基于变密度纳维 - 斯托克斯方程和非稀释物种传输方程对一个模型的解进行近似。模型中包含了盐溶液的密度、粘度、化学活性和扩散对化学成分的已知依赖性。微观尺度模型解被平均到宏观尺度，并与现有的实验观察结果进行比较。使用量纲分析和约束模拟来研究各种物理现象对微观尺度速度分布和观察到的宏观尺度弥散的影响。模拟结果用于根据潜在机制解释观察到的实验结果。揭示了所研究的各种物理化学效应重要的条件。
