Fluid rheological effects on polymer solution flows in an expansion-contraction microchannel

A fundamental understanding of the pore-scale flow dynamics of polymer solutions in porous media benefits applications such as enhanced oil recovery, groundwater remediation and microfluidic particle manipulation. The heterogeneous real-world pores are frequently represented by one or multiple consecutive expansions (i.e., pore body) and contractions (i.e., pore throat) in microfluidic models. We perform a systematic experimental study of the fluid rheological effects on polymer solution flows through a single expansion-contraction microchannel. We investigate the influences of fluid elasticity, shear thinning and inertia at both their individual and different combination levels with five types of common polymer solutions and water. All fluids are tested in a similar wide range of flow rates. The observed flow regimes and vortex developments are summarized in the same dimensionless parameter spaces for a direct comparison.