Seminar by Wenqiao Jiao

Abstract

In this presentation, I will provide a sound appraisal of the nature of the relationship between flow rate (Q) and pressure drop (\Delta P) for porous media, which is a long-standing fundamental research challenge. This relationship affects a wide variety of environmental, societal, and industrial issues, ranging from water-soil system remediation to subsurface energy optimization. While this dependence is well represented by the Kozeny-Carman formulation for homogeneous media, the fundamental nature of the relationship (Q vs \Delta P) within heterogeneous porous systems characterized by a broad range of pore sizes is still not fully understood. I will discuss the design of a set of controlled and complex porous structures and the quantification of their intrinsic permeability through detailed high-quality microfluidics experiments. I will then present an original analytical formulation that relates the overall intrinsic permeability of the porous structure to their key features. This formulation explicitly embeds the spatial variability of pore sizes into the medium permeability through a conceptualization of the system as a collection of smaller scale porous media arranged in series. The resulting analytical formulation yields permeability values that match their experimentally-based counterparts without the need for additional tunable parameters. In addition to the theoretical understanding of this important relationship, I will extend the framework to include novel experiments focusing on two paradigmatic case studies: biofilm growth and mineral dissolution, both of which affect system permeability by obstructing pore spaces.