Liquid dielectric

About: Liquid dielectric is a research topic. Over the lifetime, 3702 publications have been published within this topic receiving 45150 citations.

Spheroidal and conical shapes of ferrofluid-filled capsules in magnetic fields

Abstract: The numerical and analytical investigation of elastic capsules filled with a ferrofluid/dielectric liquid in a uniform magnetic/electric field shows a discontinuous spherical-to-conical shape transition for increasing fields with diverging strains in the conical tips.

Resistance effect of electric double layer on liquid flow in microchannel

Abstract: Poisson-Boltzmann equation for EDL (electric double layer) and Navier-Stokes equation for liquid flows were numerically solved to investigate resistance effect of electric double layer on liquid flow in microchannel. The dimension analysis indicates that the resistance effect of electric double layer can be estimated by an electric resistance number, which is proportional to the square of the liquid dielectric constant and the solid surface zeta potential, and inverse-proportional to the liquid dynamic viscosity, electric conductivity and the square of the channel width. An “electric current density balancing” (ECDB) condition was proposed to evaluate the flow-induced streaming potential, instead of conventional “electric current balancing” (ECB) condition which may induce spurious local backflow in neighborhood of the solid wall of the microchannel. The numerical results of the flow rate loss ratio and velocity profile are also given to demonstrate the resistance effect of electric double layer in microchannel.

Heat Transfer Augmentation of Parallel Flows by Means of Electric Conduction Phenomenon in Macro- and Microscales

Abstract: Electrohydrodynamic conduction phenomenon takes advantage of the electrical Coulomb force exerted on a dielectric liquid generated by externally applied electric field and dissociated charges from electrolytes. The electric conduction phenomenon can be applied to enhance or control mass transport and heat transfer in both terrestrial and microgravity environments with advantages of simplicity and no degradation of fluid properties for isothermal as well as nonisothermal liquids. This paper numerically studies the heat transfer augmentation of externally driven macro- and microscale parallel flows by means of electric conduction phenomenon. The electric conduction is generated via electrode pairs embedded against the channel wall to mainly enhance the heat transfer and not necessarily to pump the liquid. Two cases of Poiseuille and Couette parallel flows are considered where for the former, a constant external pressure gradient is applied along the channel and for the latter, the channel wall moves with a constant velocity. The electric field and electric body force distributions along with the resultant velocity fields are presented. The heat transfer enhancements are illustrated under various operating conditions for both macro- and microscales. DOI: 10.1115/1.4000977

Numerical investigation of conduction pumping of dielectric liquid film using flush-mounted electrodes

Abstract: Electrohydrodynamic conduction pumping of dielectric liquid films using flush-mounted electrodes is investigated numerically. Two major factors consisting of the ion mobility difference and electrodes’ configuration can affect the conduction pumps. The relative importance of these factors on the hydrodynamic behavior has been studied at different configurations of flush-mounted electrodes for conduction pumping of various dielectric liquids with different electrical properties. Furthermore, the effect of heterocharge layer structure on the hydrodynamic behavior of conduction pump has been studied. The electrical behavior and flow patterns of dielectric liquids with real measured mobilities are compared with the experimental results, and new features of conduction pumping are found. The numerical results indicate that in the various operating conditions, the flow direction is dictated by the dominant factor.