Magnetic-field-driven alteration in capillary filling dynamics in a narrow fluidic channel.

Abstract

We investigated pressure-driven transport of an immiscible binary system, constituted by two electrically conducting liquids, in a narrow fluidic channel under the influence of an externally applied magnetic field. The surface wettability was taken into account in the analysis considering that the walls of the channel are chemically treated to obtain various predefined contact angles as required for the study. Alterations in the capillary filling and wetting dynamics in the channel stemming from a complex interplay among different forces acting over the interface were investigated. It was shown that an alteration in the strength of the magnetic field leads to an alteration in the dynamics of the interface, which in turn, alters the filling and wetting dynamics nontrivially upon interaction with the surface tension force due to the wetted walls of the channel. It is emphasized that a contrast in properties of constituents of the binary system gives rise to an alteration in the forces being applied across the interface, leading to an intricate control over the filling and wetting dynamics for a given flow configuration and an applied field strength. We believe that the results obtained from this analysis may aid the design of microfluidic devices used for multiphase transport.