Speaker
Description
In civil engineering, it is common practise to support the walls of an open excavation, such as a borehole or trench, by filling it with fluid. The traditional and most widely used support fluids are slurries of bentonite clay in water. Semidilute aqueous solutions of high-molecular-weight polymer ("polymer fluids") are known have a variety of advantages over traditional bentonite slurries in terms of both cost and environmental impact, but they remain under-used because they are poorly understood. Here, we study the permeation of polymer fluids through porous micromodels to develop qualitative and quantitative insight into their flow through the pore space and their interactions with the solid skeleton. Our micromodels consist of custom microfluidic and millifluidic devices in a range of different geometries, complexities, and scales. We use a custom microscopy setup and a variety of imaging methods, including machine learning-assisted particle tracking velocimetry, to explore network-scale flow in 2D and pore-scale flow in 3D. Our working fluid is a semidilute aqueous solution of partially hydrolyzed polyacrylamide (HPAM). Dilute HPAM solutions have been widely studied in porous micromodels due to their well characterized shear-thinning rheology and relevance to many practical applications. At higher, semidilute concentrations, we find that entanglement and elasticity lead to hysteresis, transient effects, and a macroscopic pressure-drop-versus-flow-rate response that cannot be captured by simple shear rheology.
| Country | United Kingdom |
|---|---|
| Acceptance of the Terms & Conditions | Click here to agree |
