Electro-thermally driven transport of a non-conducting fluid in a two-layer system for MEMS and biomedical applications

Biomedical and biochemical applications pertaining to ion exchange or solvent extraction from one phase to another phase often deal with two-fluid flows, where one layer is non-conducting and the other layer is a biofluid. In the present study, we investigate the transport of two-layer immiscible fluids consisting of one non-conducting fluid and another conducting fluid layer in a micro-grooved channel, employing an alternating current electrothermal (ACET) mechanism. The conducting fluid, driven by the influence of ACET forces, transfers its induced momentum across the fluid-fluid interface allowing the movement of the non-conducting fluid layer. We use an order parameter based approach to track the interface of the two-layer fluid transport via the coupled Cahn-Hilliard-Navier-Stokes equation, while the potential and temperature distribution are solved using the Laplace equation and the thermal energy balance equation, respectively. The efficiency with which the non-conducting layer gets transported is studied with respect to various parameters. We find that the transport mechanism with the ACET process has striking advantages over the contemporary electrically actuated flow. Published by AIP Publishing.