The effects of fluid elasticity in the flow of non-Newtonian fluids in microfluidic converging/diverging geometries are investigated. We investigate the structure and dynamics of inertio-elastic flow instabilities and elastic corner vortices which develop upstream of the contraction plane, and explore their dependence on the relative magnitudes of inertia and elastic stress generated by the high deformation rates in the contraction geometry. The results show that the shape, size and evolution of these flow structures varies with the elasticity number, which is independent of the flow kinematics and is only dependent on fluid properties (viscosity, density and polymer relaxation time) and the characteristic size of the channel.
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Foundation item: Project Supported by the Schlumberger Foundation, the National Science Foundation & the Australian Research Council.
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McKinley, G.H., Rodd, L.E., Oliverira, M.S.N. et al. Extensional flows of polymer solutions in microfluidic converging/diverging geometries. J Cent. South Univ. Technol. 14, 6–9 (2007). https://doi.org/10.1007/s11771-007-0202-1
- extensional rheology
- extra pressure drop
- Couette correction