Micro/Bio/Nanofluidics (Shen) Unit would like to invite you to the seminar by Emily Chen on September 10 (Tuesday).
 
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Date:   September 10, 2024
Time:  15:00-16:00
Venue: C700, OIST
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Speaker:

Emily Chen
PhD student
Chemical and Biological Engineering
Princeton University

Title:

Viscoelastic flow instabilities in porous media: insights from pore-scale flow fields

Abstract:

Flows of viscoelastic polymer solutions in porous media are ubiquitous in industrial and environmental applications; however, it is often challenging to access pore-scale flow behavior in practical settings. Here, we overcome this challenge by using confocal microscopy and fluid refractive index-matching to directly visualize and quantify the flow behavior of viscoelastic fluids in model porous media. We examine how systematic variations in fluid rheology and pore space geometry influence the onset and features of elastic flow instabilities at the pore-scale. At the macroscopic scale, viscoelastic fluids can exhibit an anomalous increase in flow resistance, despite their shear-thinning nature in bulk rheology. To rationalize this behavior, we develop a pore-scale power balance model that captures the macroscopic flow resistance of polymer solution flow in 2-D and 3-D ordered porous media, thereby directly linking pore-scale flow fields to the macroscopic flow resistance. Further, we show that this flow-thickening phenomenon and associated flow instability can be leveraged to clean porous media soiled with model microplastics more effectively than a viscous, Newtonian fluid. Our work thus improves understanding of the physics governing viscoelastic flows from the pore to macroscopic scales and provides guidelines towards harnessing elastic flow instabilities in porous media transport applications.

Host:
Prof. Amy Shen