Fluid flow and transfer behavior of a drop translating in an electric field at intermediate Reynolds numbers

Chang, Loto S.; Berg, John C.

doi:10.1016/s0017-9310(83)80106-9

Cited by 29 publications

(4 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Taking in account circulatory flows generated by an applied electric field, Morrison (1977) and Griffiths & Morrison (1979) evaluated transfer rate enhancement and found significant electroconvective effects for stationary drops. The numerical investigation of the electrohydrodynamic effects in transfer rate enhancement for spherical drops has been extended further to include both buoyancy-driven flows (Chang, Carleson & Berg 1982;Chang & Berg 1983) and interfacial tension gradients (Chang & Berg 1985). In the present work, we focus on the pure electrohydrodynamic effects on deformable drops under neutrally buoyant conditions, leaving other complications for future research.…”

Section: Introductionmentioning

confidence: 99%

A computational analysis of electrohydrodynamics of a leaky dielectric drop in an electric field

1996

View full text Add to dashboard Cite

Axisymmetric steady flows driven by an electric field about a deformable fluid drop suspended in an immiscible fluid are studied within the framework of the leaky dielectric model. Deformations of the drop and the flow fields are determined by solving the nonlinear free-boundary problem composed of the Navier-Stokes system governing the flow field and Laplace's system governing the electric field. The solutions are obtained by using the Galerkin finite-element method with an elliptic mesh generation scheme. Under conditions of creeping flow and vanishingly small drop deformations, the results of finite-element computations recover the asymptotic results. When drop deformations become noticeable, the asymptotic results are often found to underestimate both the flow intensity and drop deformation. By tracking solution branches in parameter space with an arc-length continuation method, curves in parameter space of the drop deformation parameter D versus the square of the dimensionless field strength E usually exhibit a turning point when E reaches a critical value Ec. Along such a family of drop shapes, steady solutions do not exist for E > Ec. The nonlinear relationship revealed computationally between D and E2 appears to be capable of providing insight into discrepancies reported in the literature between experiments and predictions based on the asymptotic theory. In some special cases with fluid conductivities closely matched, however, drop deformations are found to grow with E2 indefinitely and no critical value Ec is encountered by the corresponding solution branches. For most cases with realistic values of physical properties, the overall electrohydrodynamic behaviour is relatively insensitive to effects of finite-Reynolds-number flow. However, under extreme conditions when fluids of very low viscosities are involved, computational results illustrate a remarkable shape turnaround phenomenon: a drop with oblate deformation at low field strength can evolve into a prolate-like drop shape as the field strength is increased.

show abstract

Section: Introductionmentioning

confidence: 99%

A computational analysis of electrohydrodynamics of a leaky dielectric drop in an electric field

1996

View full text Add to dashboard Cite

show abstract

“…Each distance corresponds to the effective travelling distance for the drops. This arrangement of electrodes was determined so as to obtain a uniform electric filed.16'17) The continuous phase of cyclohexane was supplied from a liquid reservoir [6] by a feed pump [7]. The dispersed phase of aqueous iodine solution was supplied from another liquid reservoir [4] to a stainless steel nozzle (0.1 cm o.d., 0.06cm i.d.)…”

Section: Methodsmentioning

confidence: 99%

An experimental study of mass transfer rate in the dispersed phase for single charged drops in a dielectric liquid under a uniform electric field.

Yamaguchi

Takamatsu

Yoshida

et al. 1985

J. Chem. Eng. Japan

View full text Add to dashboard Cite

Mass transfer of iodine from single charged drops of aqueous iodine solution into a continuous phase of cyclohexane was measured during the overall process of formation, free fall and coalescence of the drops in a range of uniform electric field strength up to 2.4 kV/cm. The total amount of iodine transferred was separated into that during drop formation and that during the subsequent stages. Each mass transfer mechanism during the formation and the free fall of drops in the electric field was investigated with theoretical and empirical equations in the literature, which were obtained in the absence of an electric field.The mechanismof mass transfer during the formation of the charged drops in the presence of an electric field and that during free fall of the drops are the same as those obtained in the absence of an electric field. The enhancement of mass transfer obtained in the electric field is due to the increased effective inter facial area per volume of dispersed phase and to the increased moving velocity of the drops caused by applying the electric field.

show abstract

“…higher droplet velocities resulting from EHD forces of repulsion exerted on the charged drops in the direction of motion (Thornton, 1968;Bailes, 1981;Takamatsu et al, 1983;Yamaguchi et al, 1985;Vu and Carleson, 1986); enhanced circulations inside and around droplets due to the tangential component of the EHD forces exerted on the droplet surface (Morrison, 1977;Griffiths and Morrison, 1979;Chang et al, 1982;Chang and Berg, 1983); induced droplet oscillations by electric field due to the droplet deformation effect (Thornton, 1976;Wham and Byers, 1987;Scott and Byers, 1989;Basaran et al, 1989;Scott et al, 1990;Yang and Carleson, 1991); interfacial-tension-induced flow by the local variations in the effective interfacial tension due to the presence of electrical charges (Austin et al, 1971;Iyer and Sawistowski, 1974;Carleson and Berg, 1984;Berg, 1985a, 1985b;Carleson and Fuller, 1987). The basic techniques to achieve electrically enhanced liquid-liquid extraction are briefly summarized in Table 1.…”

Section: Electric Fieldsmentioning

confidence: 99%

The effect of electric field on mass transfer from drops dispersed in a viscous liquid

He¹,

Baird²,

Chang³

1993

Can. J. Chem. Eng.

View full text Add to dashboard Cite

Mass transfer of benzoic acid from drops dispersed into a continuous phase of mineral oil with high viscosity has been investigated both with and without an imposed non‐uniform d.c. electric field. Total mass transfer efficiency was significantly enhanced in the presence of the high voltage electric field. The results indicate that the application of the electric field to the drop formation process does not change the fundamental mass transfer mechanisms and the mass transfer during drop free fall can also be described by existing mass transfer models. The results also suggest that the high viscosity of the continuous phase inhibits the drops oscillation as well as circulation when the drop sizes become smaller under the applied high voltage electric field. Therefore the significant enhancement of mass transfer efficiency in the present work is mainly due to the increased specific interfacial area.

show abstract

Fluid flow and transfer behavior of a drop translating in an electric field at intermediate Reynolds numbers

Cited by 29 publications

References 11 publications

A computational analysis of electrohydrodynamics of a leaky dielectric drop in an electric field

A computational analysis of electrohydrodynamics of a leaky dielectric drop in an electric field

An experimental study of mass transfer rate in the dispersed phase for single charged drops in a dielectric liquid under a uniform electric field.

The effect of electric field on mass transfer from drops dispersed in a viscous liquid

Contact Info

Product

Resources

About