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Measurements and simulations of time-dependent flow fields within an electrokinetic micromixer

Published online by Cambridge University Press:  14 April 2011

DOMINIK P. J. BARZ ,
HAMID FARANGIS ZADEH  and
PETER EHRHARD
DOMINIK P. J. BARZ*
Affiliation:
IKET, Karlsruhe Institute of Technology, Herrmann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
HAMID FARANGIS ZADEH
Affiliation:
IKET, Karlsruhe Institute of Technology, Herrmann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
PETER EHRHARD
Affiliation:
Fluid Mechanics, Biochemical & Chemical Engineering, Dortmund University of Technology, Emil-Figge-Str. 68, D-44221 Dortmund, Germany
*
†Present address: Queen's University, Department of Chemical Engineering, Dupuis Hall 213, Kingston, ON K7L 3N6, Canada. Email address for correspondence: [email protected]
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Abstract

We investigate the flow field in an electrokinetic micromixer. The concept of the micromixer is based on the combination of an alternating electrical field applied to a pressure-driven base flow in a meander–channel geometry. The presence of the electrical field leads to an additional electro-osmotic velocity contribution, which results in a complex flow field within the meander bends. The velocity fields within the meander are measured by means of a microparticle-image velocimetry method. Furthermore, we introduce a mathematical model, describing the electrical and fluid-mechanical phenomena present within the device, and perform simulations comparable to the experiments. The comparison of simulations and experiments reveals good agreement, with minor discrepancies in flow topology, obviously caused by small but crucial differences between experimental and numerical geometries. In detail, simulations are performed for sharp corners of the bends, while in the experiments these corners are rounded due to the microfabrication process.

JFM classification

Micro-/Nano-fluid dynamics: Microfluidics Flow Control: Mixing enhancement
Type
Papers
Information
Journal of Fluid Mechanics , Volume 676 , 10 June 2011 , pp. 265 - 293
Copyright
Copyright © Cambridge University Press 2011

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References

REFERENCES

Atkins, P. W. 1997 Physical Chemistry. Oxford University Press.Google Scholar
Barz, D. P. J. & Ehrhard, P. 2005 Model and verification of electrokinetic flow and transport in a micro electrophoresis device. Lab on a Chip 5, 949–958.CrossRefGoogle Scholar
Barz, D. P. J., Farangis Zadeh, H. & Ehrhard, P. 2008 Investigations of laminar flow and mass transport in a twice-folded microchannel. AIChE J. 54, 381–393.CrossRefGoogle Scholar
Barz, D. P. J., Vogel, M. J. & Steen, P. H. 2009 Determination of the zeta potential of substrates by droplet deflection. Part I. The influence of ionic strength and ph value of an aqueous electrolyte in contact with a borosilicate surface. Langmuir 25, 1842–1850.CrossRefGoogle Scholar
Bhattacharyya, S., Zheng, Z. & Conslik, A. T. 2005 Electro-osmotic flow in two-dimensional charged micro- and nanochannels. J. Fluid Mech. 540, 247–267.CrossRefGoogle Scholar
Burgreen, D. & Nakache, F. R. 1964 Electrokinetic flow in ultrafine capillary slits. J. Phys. Chem. 68, 1084–1091.Google Scholar
Conlisk, A. T., McFerran, J., Zheng, Z. & Hansford, D. 2002 Mass transfer and flow in electrically charged micro- and nanochannels. Anal. Chem. 74, 2139–2150.CrossRefGoogle ScholarPubMed
Czarske, J., Büttner, L., Razik, T. & Müller, H. 2002 Boundary layer velocity measurements by a laser Doppler profile sensor with micrometer spatial resolution. Meas. Sci. Technol. 13, 1979–1989.Google Scholar
Erickson, D. & Li, D. 2002 Microchannel flow with patchwise and periodic surface heterogeneity. Langmuir 18, 8949–8959.CrossRefGoogle Scholar
Freitag, A., Dietrich, T. & Scholz, R. 2000 Glass as material for microreaction technology. In Proc. of the 4th Intl Conf. on Microreaction Technology, IMRET 4, pp. 48–54. Atlanta, USA.Google Scholar
Gascoyne, P. R. C. & Vykoukal, J. 2002 Particle separation by dielectrophoresis. Electrophoresis 23, 1973–1983.3.0.CO;2-1>CrossRefGoogle ScholarPubMed
Ghosal, S. 2002 Lubrication theory for electro-osmotic flow in a microfluidic channel of slowly varying cross-section and wall charge. J. Fluid Mech. 459, 459.CrossRefGoogle Scholar
Hardt, S. & Schönfeld, F. 2003 Laminar mixing in different interdigital micromixers. Part II. Numerical simulations. AIChE J. 49, 578–584.CrossRefGoogle Scholar
Hunter, R. J. 1981 Zeta Potential in Colloid Science: Principles and Applications. Academic Press.Google Scholar
Kim, M. J., Beskok, A. & Kihm, K. D. 2002 Electro-osmosis-driven micro-channel flows: a comparative study of microscopic particle image velocimetry measurements and numerical simulations. Exp. Fluids 33, 170–180.CrossRefGoogle Scholar
Kirby, B. J. & Hasselbrink, E. F. jr. 2004 Zeta potential of microfluidic substrates. Part I. Theory, experimental techniques and effects on separations. Electrophoresis 25, 187–202.CrossRefGoogle Scholar
Kohlrausch, F. 1897 Über Concentrations-Verschiebungen durch Electrolyse von Lösungen und Lösungsgemischen. Ann. Phys. 62, 209.CrossRefGoogle Scholar
Laser, D. J. & Santiago, J. G. 2004 A review of micropumps. J. Micromech. Microengng 14, R35–R64.CrossRefGoogle Scholar
Lin, H., Storey, B. D., Oddy, M. H., Chuan-Hua, C. & Santiago, J. G. 2004 Instability of electrokinetic flows with conductivity gradients. Phys. Fluids 16, 1922–1935.CrossRefGoogle Scholar
Liu, R. H., Stremler, A., Sharp, K. V., Olson, M. G., Santiago, J. G., Adrian, R. J., Aref, H. & Beebe, D. J. 2000 Passive mixing in a three-dimensional serpentine microchannel. J. Microelectromech. Syst. 9, 190–197.CrossRefGoogle Scholar
MacInnes, J. M., Du, X. & Allen, R. W. K 2003 Prediction of electrokinetic and pressure flow in a microchannel T-junction. Phys. Fluids 15, 1992–2005.CrossRefGoogle Scholar
Manz, A., Graber, N. & Widmer, H. M. 1990 Miniaturized total chemical analysis systems: a novel concept for chemical sensing. Sensors Actuators B 1, 244–248.Google Scholar
Matsumoto, R., FarangisZadeh, H. Zadeh, H. & Ehrhard, P. 2005 Quantitative measurement of depth averaged concentration fields in microchannels by means of a fluorescence intensity method. Exp. Fluids 39, 722–729.CrossRefGoogle Scholar
Meinhart, C. D., Wereley, S. T. & Gray, M. 2000 Volume illumination for two-dimensional particle image velocimetry. Meas. Sci. Technol. 11, 809–814.CrossRefGoogle Scholar
Meinhart, C. D., Wereley, S. T. & Santiago, J. G. 1999 a Micron-resolution velocimetry techniques. In Laser Techniques Applied to Fluid Mechanics (ed. Adrian, R. J.), pp. 57–70. Springer.Google Scholar
Meinhart, C. D., Wereley, S. T. & Santiago, J. G. 1999 b PIV measurements of a microchannel flow. Exp. Fluids 27, 414–419.CrossRefGoogle Scholar
Meisel, I. & Ehrhard, P. 2006 Electrically-excited (electro-osmotic) flows in microchannels for mixing applications. Eur. J. Mech. B/Fluids 25, 491–504.CrossRefGoogle Scholar
Oddy, M. H., Santiago, J. G. & Mikkelsen, J. C. 2001 Electrokinetic instability micromixing. Anal. Chem. 73, 5822–5832.CrossRefGoogle ScholarPubMed
Ould El Moctar, A., Aubry, N. & Batton, J. 2003 Electro-hydrodynamic micro-fluidic mixer. Lab on a Chip 3, 273–280.Google Scholar
Patankar, N. A. & Hu, H. H. 1998 Numerical simulation of electro-osmotic flow. Anal. Chem. 70, 1870–1881.CrossRefGoogle Scholar
Paul, P. H., Garguilo, M. G. & Rakestraw, D. J. 1998 Imaging of pressure- and electrokinetically-driven flows through open capillaries. Anal. Chem. 70, 2459–2467.CrossRefGoogle ScholarPubMed
Qian, S. & Bau, H. H. 2002 A chaotic electro-osmotic stirrer. Anal. Chem. 74, 3616–3625.CrossRefGoogle Scholar
Rice, C. L. & Whitehead, R. 1965 Electrokinetic flow in a narrow capillary. J. Phys. Chem. 11, 4017–4024.CrossRefGoogle Scholar
Sadr, R., Yoda, M., Zheng, Z. & Conlisk, A. T. 2004 An experimental study of electro-osmotic flow in rectangular microchannels. J. Fluid Mech. 506, 357–367.CrossRefGoogle Scholar
Santiago, J. G., Wereley, S. T., Meinhart, C. D., Beebe, R. & Adrian, R. J. 1998 A particle image velocimetry system for microfluidics. Exp. Fluids 25, 316–319.CrossRefGoogle Scholar
Saville, D. A. 1997 Electrohydrodynamics: the Taylor–Melcher leaky dielectric model. Annu. Rev. Fluid Mech. 29, 27–64.CrossRefGoogle Scholar
Scales, P. J., Grieser, F. & Healy, T. W. 1992 Electrokinetics of the silica-solution interface: a flat plate streaming potential study. Langmuir 8, 965–974.CrossRefGoogle Scholar
Smoluchowski, M v. 1903 Contribution à la théorie de l'endosmose électrique et de quelques phenoménes corrélatifs. Bull. Intl Acad. Sci. Cracovie 8, 182–200.Google Scholar
Stone, H. A., Stroock, A. D. & Ajdari, A. 2004 Engineering flows in small devices: microfluidics toward a lab-on-a-chip. Annu. Rev. Fluid Mech. 36, 381–411.Google Scholar
Stroock, A. D., Dertinger, S. K. W., Ajdari, A., Mezić, I., Stone, H. A. & Whitesides, G. M. 2002 Chaotic mixer for microchannels. Science 295, 647–651.CrossRefGoogle ScholarPubMed
Tieu, A. K., Mackenzie, M. R. & Li, E. B. 1995 Measurements in microscopic flow with a solid-state LDA. Exp. Fluids 19, 293–294.CrossRefGoogle Scholar
Van Dyke, M. 1975 Perturbation Methods in Fluid Mechanics. The Parabolic Press.Google Scholar
Ward-Smith, J. 1980 Internal Fluid Flow - The Fluid Dynamics of Flow in Pipes and Ducts. Clarendon Press.Google Scholar
Yamaguchi, Y., Takagi, F., Yamashita, K., Nakamura, H, Maeda, H., Sotowa, K., Kusakabe, K., Yamasaki, Y. & Morooska, S. 2004 3-D Simulation and visualization laminar flow in a microchannel with hair-pin curves. AIChE J. 50, 1530–1535.CrossRefGoogle Scholar
Yang, Z., Matsumoto, S., Goto, H., Matsumoto, M. & Meaeda, R. 2001 Ultrasonic micromixer for microfluidic systems. Sensors Actuators A 93, 2666–272.CrossRefGoogle Scholar
Yi, M., Qian, S. & Bau, H. H. 2002 A magnetohydrodynamic chaotic stirrer. J. Fluid Mech. 468, 153–177.CrossRefGoogle Scholar