Numerical Simulation of Electroosmotic Flow with Step Change in Zeta Potential
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IMST018.pdf
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167.55 KB
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Adobe PDF
Checksum (MD5)
52c75e41fcf49d5b1a292b1a08d8261f
Author(s)
Chen, X.
Lam, Yee Cheong
Chen, X. Y.
Chai, J.C.
Yang, C.
Date Issued
January 2005
Series/Report no.
Innovation in Manufacturing Systems and Technology (IMST);
Abstract
Electroosmotic flow is a convenient mechanism for transporting polar fluid in a microfluidic device. The flow is generated through the application of an external electric field that acts on the free charges that exists in a thin Debye layer at the channel walls. The charge on the wall is due to the chemistry of the solid-fluid interface, and it can vary along the channel, e.g. due to modification of the wall. This investigation focuses on the simulation of the electroosmotic flow (EOF) profile in a cylindrical microchannel with step change in zeta potential. The modified Navier-Stoke equation governing the velocity field and a non-linear two-dimensional Poisson-Boltzmann equation governing the electrical double-layer (EDL) field distribution are solved numerically using finite control-volume method. Continuities of flow rate and electric current are enforced resulting in a non-uniform electrical field and pressure gradient distribution along the channel. The resulting parabolic velocity distribution at the junction of the step change in zeta potential, which is more typical of a pressure-driven velocity flow profile, is obtained.
Subjects
Electroosmotic flow
Electrical double-layer
Pressure-driven flow
Zeta potential
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