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Mixing Behaviors of Shear-Thinning Fluids in Serpentine-Channel Micromixers
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.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1108456Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1509
 J. A. Pathak, D. Ross, and K. B. Migler, “Elastic flow instability, curved streamlines, and mixing in microfluidic flows,” Phys. Fluids, vol. 16, pp. 4028-4034, 2004.
 Y. C. Lam, H. Y. Gan, N. T. Nguyen, and H. Lie, “Micromixer based on viscoelastic flow instability at low Reynolds number,” Biomicrofluidics, vol. 3, 014106 (14 pages), 2009.
 C. Srisamran and S. Devahastin, “Numerical simulation of flow and mixing behavior of impinging streams of shear-thinning fluids,” Chem. Eng. Sci., vol. 61, pp. 4884-4892, 2006.
 J. Aubin, L. Prat, C. Xuereb, and C. Gourdon, “Effect of microchannel aspect ratio on residence time distributions and the axial dispersion coefficient,” Chem. Eng. process, vol. 48, 554–559, 2009.
 H. Peerhossaini, C. Castelain, and Y. Le Guer, “Heat-exchanger design based on chaotic advection,” Exp. Therm. Fluid Sci., vol. 7, pp. 333-344, 1993.
 F. Jiang, K. S. Drese, S. Hardt, M. Küpper, and F. Schönfeld, “Helical flows and chaotic mixing in curved microchannels,” AIChE J., vol. 50, pp. 2297-2305, 2004. F. Garofalo, A. Adrover, S. Cerbelli, and M. Giona, “Spectral characterization of static mixers. The S-shaped micromixer as a case study,” AIChE J., vol. 56, pp. 318-335, 2010.
 F. Garofalo, A. Adrover, S. Cerbelli, and M. Giona, “Spectral characterization of static mixers. The S-shaped micromixer as a case study,” AIChE J., vol. 56, pp. 318-335, 2010.
 C.-Y. Wu and R.-T. Tsai, “Fluid mixing via multi-directional vortices in converging-diverging meandering microchannels with semi-elliptical side walls,” Chem. Eng. J., vol. 217, pp. 320-328, 2013.
 R. P. Chhabra and J. F. Richardson, Non-Newtonian Flow, and Applied Rheology: Engineering Applications. 2nd ed. Butterworth-Heinemann, Oxford, 2008.
 F. Fellouah, C. Castelain, A. Ould-El-Moctar, and H. Peerhossaini, “The Dean instability in power-law and Bingham fluids in a curved rectangular duct,” J. Non-Newtonian Fluid Mech., vol. 165, pp. 163–173, 2010.
 U. Meseth, T. Wohland, R. Rigler, and H. Vogel, “Resolution of fluorescence correlation measurements,” Biophysical J., vol. 76, pp. 1619-1631, 1999.
 A. L. Ventresca, Q. Cao, and A. K. Prasad, “The influence of viscosity ratio on mixing effectiveness in a two-fluid laminar motionless mixer,” Can. J. Chem. Eng., vol. 80, pp. 614-621, 2002.
 J. Boss, “Evaluation of the homogeneity degree of mixture,” Bulk Solids Handl., vol. 6, pp. 1207-1215, 1986.
 F. Delplac and J. C. Leuliet, “Generalized Reynolds number for the flow of power-law fluids in cylindrical ducts of arbitrary cross-section,” Chem. Eng. J., Vol. 56, pp. 33-37, 1995.