Abstract: This study aims to investigate the mixing behaviors of
deionized (DI) water and carboxymethyl cellulose (CMC) solutions in
C-shaped serpentine micromixers over a wide range of flow
conditions. The flow of CMC solutions exhibits shear-thinning
behaviors. Numerical simulations are performed to investigate the
effects of the mean flow speed, fluid properties and geometry
parameters on flow and mixing in the micromixers with the serpentine
channel of the same overall channel length. From the results, we can
find the following trends. When convection dominates fluid mixing,
the curvature-induced vortices enhance fluid mixing effectively. The
mixing efficiency of a micromixer consisting of semicircular C-shaped
repeating units with a smaller centerline radius is better than that of a
micromixer consisting of major segment repeating units with a larger
centerline radius. The viscosity of DI water is less than the overall
average apparent viscosity of CMC solutions, and so the effect of
curvature-induced vortices on fluid mixing in DI water is larger than
that in CMC solutions for the cases with the same mean flow speed.