Abstract
The stability of electrokinetic flow in a rectangular cross-section microfluidic channel with transverse conductivity gradients and driven by streamwise electric fields was explored. Such a system exhibits a critical electric field above which the flow is highly unstable, resulting in fluctuating velocities and rapid stirring. The problem was studied using theoretical and numerical analyses, as well as experimental observations. It was found that the internally generated electric body force was responsible for the instability, whereas the diffusion of ion species provided a stabilizing mechanism. Various models including two-dimensional and depth-averaged formulations were studied; modeling results compare well with experimental observations. These results have application to the design and control of on-chip assays that require high conductivity gradients, and provide a rapid mixing mechanism for low Reynolds number flow in microchannels.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
J. Baygents, F. Baldessari, Electrohydrodynamic instability in a thin fluid layer with an electrical conductivity gradient, Phys. Fluids, Vol.10,1, 301–311, 1998.
C.-H. Chen, J.G. Santiago, Electrokinetic instability in high concentration gradient microflows, Proceedings of IMECE-2002, CD Vol.1, #33563, 2002.
C.-H. Chen, H. Lin, S.K. Lele, J.G. Santiago, Convective and absolute electrokinetic instability with conductivity gradients, J. Fluid Mech., in press, 2004.
J.F. Hoburg, J.R. Melcher, Internal electrohydrodynamic instability and mixing of fluids with orthogonal field and conductivity gradients, J. Fluid Mech., Vol.73, 333, 1976.
H. Lin, B.D. Storey, M.H. Oddy, C.-H. Chen, J.G. Santiago, Instability of electrokinetic microchannel flows with conductivity gradients, Phys. Fluids, Vol.16(6), 1922–1935, 2004.
S. Liu, S. Masliyah, Single fluid flow in porous media, Chem. Eng. Comm. Vol.148–150, 653–732, 1996.
J.R. Melcher, G.I. Taylor, Electrohydrodynamics: a review of the role of interfacial stresses, Annu. Rev. Fluid. Mech., Vol.1, 111–146, 1969.
M.H. Oddy, J.G. Santiago, J.C. Mikkelson, Electrokinetic instability micromixing, Anal. Chem., Vol.73, 5822–5832, 2001.
R.F. Probstein, Physicochemical Hydrodynamics, John Willey & Sons, New York, 1994.
B.D. Storey, B.S. Tilley, H. Lin, J.G. Santiago, Electrokinetic instabilities in thin microchannels, Phys. Fluids, in review, 2004.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2005 Springer
About this paper
Cite this paper
Lin, H., Oddy, M.H., Santiago, J.G. (2005). Electrokinetic flow Instabilities in Microfluidic Systems. In: Gutkowski, W., Kowalewski, T.A. (eds) Mechanics of the 21st Century. Springer, Dordrecht. https://doi.org/10.1007/1-4020-3559-4_23
Download citation
DOI: https://doi.org/10.1007/1-4020-3559-4_23
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-3456-5
Online ISBN: 978-1-4020-3559-3
eBook Packages: EngineeringEngineering (R0)