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

Abstract

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.