SKM 2023 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Poster Session II
CPP 35.8: Poster
Mittwoch, 29. März 2023, 11:00–13:00, P1
Improved displacement efficiency in porous media by invasion of viscoelastic fluids — •Michael Jung1,2, Pegah Shakeri1,2, and Ralf Seemann1,2 — 1Universität des Saarlandes, Saarbrücken, Germany — 2Max Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
Improving the displacement efficiency of capillary entrapments in porous media by adding high molecular weight polymers to the invading phase has a variety of industrial applications. Apart from an increased viscosity contrast compared to water flooding, the flow of viscoelastic polymer solutions exhibits unstable flow behavior even at small Reynolds numbers, which can lead to an additional displacement mechanism of the capillary entrapments. We use a microfluidic approach to reveal the underlying mechanism of this enhanced displacement by first considering a random array of cylindrical posts to identify fundamental differences in displacement processes for elastic and non-elastic fluids. Then, to focus directly on displacement processes driven solely by elastic stresses and to exclude the effects of viscous stresses, we consider a single capillary entrapment connected to two symmetric serpentine channels. We show that the unique viscoelastic fluid features, such as the emergence of a significant first normal stress difference, combined with the curved flow geometry, lead to purely elastic instability and elastic secondary flow, which in turn generate the stresses required to overcome the capillary threshold and displace capillary entrapment.