Viscous Fingering Instability of Complex Fluids in a Radial Hele-Shaw Cell

Date
2024-03-15
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Abstract
When a less-viscous fluid displaces another fluid of higher viscosity in a porous medium, instability can develop at the interface between the two fluids. The instability manifests itself in the form of finger-like patterns of the displacing fluid propagating through the displaced one. In this work, viscous fingering instabilities involving complex fluids in a radial Hele-Shaw is investigated. Many fluids in our lives such as shaving foams, glues, flour-water dough, mayonnaise, and paints are complex fluids which exhibit multiple non-Newtonian properties simultaneously such as shear-thinning or shear-thickening, yield stress, and viscoelastic effects. First, the effects of normal stress differences of dilute low molecular weight poly(ethylene oxide) (PEO) solutions on viscous fingering instability are studied. Second, we investigate the instabilities associated with air invading foam in Hele-Shaw cell. Third, we examine the effects of water in viscous fingering instabilities of air displacing mineral oil. Fourth, the instability at the interface between two parallel flows of immiscible liquids through a uniform planar pore is studied by using linear stability analysis. We pose important questions: How does normal stresses affect immiscible radial viscous fingering? How does fingering occur into foam? Is it similar to that of a single-phase liquid? The experimental observations reveal nonmonotonic and opposing effects are evident depending on the molecular weight of the PEO and the stage of the radial viscous fingering evolution. We have identified three different flow regimes in the immiscible radial displacement flows of air invading foam in Hele-Shaw cell. The presence of a small volume of water leads to significantly different fingering patterns than that when no water is present. The outcomes are significant because the results demonstrate new behaviors for displacement flow of complex fluids.
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Keywords
viscous fingering, elastic instability interfacial instability, Hele-Shaw, poly(ethylene oxide) solution, elastic fluids, foam displacement, foam flow, air injection, three phase displacement, mineral oil, instability, stability analysis, oil sands, steam-assisted gravity drainage, multiphase flow
Citation
Lee, Y. H. (2024). Viscous fingering instability of complex fluids in a radial Hele-Shaw cell (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.