On the use of microscale modeling to improve macroscale non-dilute flow and transport models

Abstract:

Recently derived macroscale models for non-dilute flow and transport in porous media have relied on fitting parameters that are not based on physical phenomena and have been shown to depend on system parameters. This severely limits the predictive power of these models and shows that a fundamental understanding of non-dilute flow and transport is lacking. While experimental work has shown that these systems depend on density, viscosity, velocity, and chemical activity, the microscale phenomena are not well understood. To improve our mechanistic understanding of such systems, we examine non-dilute transport from a fundamental microscale, or pore-scale, continuum modeling perspective. The variable-density Navier-Stokes equations and a non-dilute species transport equation are solved and the results are averaged to the macroscale. This approach allows for the isolation of each parameter to further our understanding on non-dilute flow and transport. Insight from averaged microscale simulations is used to formulate new closure relations and derive an improved macroscale model.