Non-Equilibrium Modeling of AC Electroosmosis in Microfluidic Channels --Parametrical Studies--
M. Přibyl, P. Červenka, J. Hrdlička, and D. Šnita
Institute of Chemical Technology, Prague, Czech Republic
Abstract
This Non-equilibrium mathematical model based on the balances of mass, momentum and ionic components and the Poisson equation has been developed. The model describes transport processes in the entire time and space domains including electric double layers. We assume that the system works below the electrochemical limit. The electroosmotic transport in various microfluidic channels is studied. It is considered that the channels contain a periodically repeating spatial motif. Hence the transport processes are studied in one periodic segment of the channels. Non-planar asymmetric electrodes, on which an AC electric field is imposed, are deposited on one channel wall. The model equations are solved using the finite element software COMSOL. In order to carry out the numerical simulations, a strongly anisotropic mesh of finite elements is developed. The stable periodic regimes are obtained by the time-integration of the model equations. In this work, we focus on: (i) parametric analysis of the stable periodic regimes — time-averaged characteristics (the net velocity, the current-voltage phase shift, the integral Coulomb force etc.) are computed in the parameter space, (ii) determination of regions of the parameter space, in which the net velocity attains high values, (iii) visualization of velocity fields and fields of other model variables in various phases of the AC electric signal.
Keywords - AC electroosmosis, microchip, mathematical modeling, non-equilibrium model, Poisson equation
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