Welcome to the next lecture in the PoreLab Lecture Series for the semester.
Who: Professor Salvatore Torquato, from Princeton University, USA
When: Wednesday 10 May at 15:00 (Oslo time)
Title: Microstructure-Dependent Predictions of the Transport Properties of Porous Media
I describe theoretical estimates of the effective transport characteristics of fluid-saturated porous media that are based on rigorous microstructure-property relations. We are particularly interested in predicting the formation factor F, mean survival time τ , principal NMR (diffusion) relaxation time T1, principal viscous relaxation time Θ1, and fluid permeability k. We consider the transport properties of “hyperuniform” and nonhyperuniform models of porous media. Disordered hyperuniform materials are exotic amorphous states of matter that have attracted great attention in the physical, mathematical and biological science but little is known about their fluid transport characteristics. Among other results, we show how the fluid permeabilities of hyperuniform porous media perform relative to those of nonhyperuniform ones. We find that the velocity fields in nonhyperuniform porous media are generally much more localized over the pore space compared to those in their hyperuniform counterparts, which has implications for their fluid permeabilities. Rigorous bounds on transport properties suggest a new approximate formula for the fluid permeability that provides reasonably accurate permeability predictions of a class of hyperuniform and nonhyperuniform porous media in which the pore space is well connected. I will also describe the time-dependent diffusion spreadability S(t), which yields microstructural information across length scales and is directly connected to nuclear magnetic resonance relaxation measurements. These studies shed new light on the microstructural characteristics that determine the transport properties of general porous media