Lattice Boltzmann Study of Electrohydrodynamic Drop Deformation With Large Density Ratio

Abstract

The lattice Boltzmann method (LBM) has been applied to electrohydrodynamics (EHD) in recent years. In this paper, ShanÀChen (SC) single-component multiphase LBM is developed to study large-density-ratio EHD problems. The deformation/motion of a droplet suspended in a viscous liquid under an applied external electric field is studied with three different electric field models. The three models are leaky dielectric model, perfect dielectric model and constant surface charge model. They are used to investigate the effects of the electric field, electric properties of liquids and electric charges. The leaky dielectric model and the perfect dielectric model are validated by the comparison of LBM results with theoretical analysis and available numerical data. It shows that the SC LBM coupled with these electric field models is able to predict the droplet deformation under an external electric field. When net charges are present on the droplet surface and an electric field is applied, both droplet deformation and motion are reasonably predicted. The current numerical method may be an effective approach to analyze more complex EHD problems.

Entropic lattice Boltzmann model for charged leaky dielectric multiphase fluids in electrified jets

“…In particular, the use of the entropic lattice Boltzmann method (ELBM) allows to extend the LBM application also in the presence of intense electrostatic forces, acting on charged leaky dielectric liquids, which is of main interest for modeling the electrospinning process. In this context, the largest part of the charge is modeled to lie along the interface between the liquid and the gaseous phase in similarity with previous works [31,32]. Further, the present ELBM is generalized to the case of non-Newtonian flows with a shear-thinning viscosity in order to account for the rheological properties of electrospun jets.…”

“…Indeed, the constant surface charge model was already adopted in Refs. [31,32] as a strategy to simplify the charge transport and distribution on the droplet interface. Nonetheless, the constant surface charge model fails in describing a distributed charge on the drop interface whenever the charge density is high, since the curvature surface alters the local charge density [16].…”

Movable and Focus-Tunable Lens Based on Electrically Controllable Liquid: A Lattice Boltzmann Study

“…The permittivity can be expressed as [ 56 ] where and are the dielectric constants of the liquid and gas phases, respectively. and are the densities of the liquid and gas phases, respectively.…”

Experimental study on liquid spray and small droplet formation in ethanol-oil system in a DC electric field

“…Despite some discrepancy, following studies had proved the leaky dielectric theory to be correct for analyzing the flow and deformation pattern when no net charge exists on the droplet surface (Vizika and Saville, 1992;Feng and Scott, 1996;Reddy and Esmaeeli, 2009). Many literatures have discussed the charged single droplet deformation and breakup processes influenced by physical properties such as electrical conductivity, viscosity, surface tension and density, which is still ongoing (Jong-Wook and Seung-Man, 2000;Matsuyama, et al, 2007;Ristenpart et al, 2009;Jalaal et al, 2010;Raisin et al, 2011, Li et al, 2011.…”