title: Numerical analysis of field-modulated electroosmotic flows in microchannels with arbitrary numbers and configurations of discrete electrodes.
abstract: The formation of an electric double layer and electroosmosis are important theoretic foundations associated with microfluidic systems. Field-modulated electroosmotic flows in microchannels can be obtained by applying modulating electric fields in a direction perpendicular to a channel wall. This paper presents a systematic numerical analysis of modulated electroosmotic flows in a microchannel with discrete electrodes on the basis of the Poisson equation of electric fields in a liquid-solid coupled domain, the Navier-Stokes equation of liquid flow, and the Nernst-Planck equation of ion transport. These equations are nonlinearly coupled and are simultaneously solved numerically for the electroosmotic flow velocity, electric potential, and ion concentrations in the microchannel. A number of numerical examples of modulated electroosmotic flows in microchannels with discrete electrodes are presented, including single electrodes, symmetric/asymmetric double electrodes, and triple electrodes. Numerical results indicate that chaotic circulation flows, micro-vortices, and effective fluid mixing can be realized in microchannels by applying modulating electric fields with various electrode configurations. The interaction of a modulating field with an applied field along the channel is also discussed.
authors.affiliation: Mechanics Department of Huazhong, University of Science & Technology, Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China.
authors.forename: Kan
authors.initials: K
authors.lastname: Chao
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: Jiankang
authors.initials: J
authors.lastname: Wu
mesh_terms: D004566:Electrodes; D053841:Electroosmosis / Q000295:instrumentation / Q000379:methods*; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical