Numerical simulation of the deformation of charged drops of electrolyte

Davidson, Malcolm R.; Berry, Joseph D.; Harvie, Dalton J. E.

doi:10.2495/afm140181

Cited by 3 publications

(8 citation statements)

References 13 publications

(40 reference statements)

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“…Their results include computations of tip streaming drops. Related numerical work includes [43][44][45]. A strong motivation for theoretical and numerical analysis of the electrokinetic models is their significance in microfluidic devices, for which electrokinetic techniques have been among the most important methods for the manipulation of drops and bubbles [46].…”

Section: Introductionmentioning

confidence: 99%

Deformation and stability of a viscous electrolyte drop in a uniform electric field

Wang

Siegel

2019

Phys. Rev. Fluids

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We study the deformation and breakup of an axisymmetric electrolyte drop which is freely suspended in an infinite dielectric medium and subjected to an imposed electric field. The electric potential in the drop phase is assumed small, so that its governing equation is approximated by a linearized Poisson-Boltzmann or modified Helmholtz equation (the Debye-Hückel regime). An accurate and efficient boundary integral method is developed to solve the low-Reynolds-number flow problem for the time-dependent drop deformation, in the case of arbitrary Debye layer thickness. Extensive numerical results are presented for the case when the viscosity of the drop and surrounding medium are comparable. Qualitative similarities are found between the evolution of a drop with a thick Debye layer (characterized by the parameter χ ≪ 1, which is an inverse dimensionless Debye layer thickness) and a perfect dielectric drop in an insulating medium. In this limit, a highly elongated steady state is obtained for sufficiently large imposed electric field, and the field inside the drop is found to be well approximated using slender body theory. In the opposite limit χ ≫ 1, when the Debye layer is thin, the drop behaves as a highly conducting drop, even for moderate permittivity ratio Q = ǫ 1 /ǫ 2 , where ǫ 1 , ǫ 2 is the dielectric permittivity of drop interior and exterior, respectively. For parameter values at which steady solutions no longer exist, we find three distinct types of unsteady solution or breakup modes. These are termed conical end formation, end splashing, and open end stretching. The second breakup mode, end splashing, resembles the breakup solution presented in a recent paper [R. B. Karyappa et al., J. Fluid Mech. 754, 550-589 (2014)]. We compute a phase diagram which illustrates the regions in parameter space in which the different breakup modes occur.

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Section: Introductionmentioning

confidence: 99%

Deformation and stability of a viscous electrolyte drop in a uniform electric field

Wang

Siegel

2019

Phys. Rev. Fluids

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“…9To account for interfacial charges, two methods were evaluated elsewhere (Davidson et al, 2014), which are the delta function formulation and another one adapted from (Liu et al, 2000) that accounts for jump in electric displacement due to interfacial charges and discontinuity in permittivity across interface. Davidson and co-workers (Davidson et al, 2014) concluded that the second one was more satisfactory to represent the electrical potential jump in the interface. Explicit expressions and formulations for the method can be found in (Davidson et al, 2014, Liu et al, 2000.…”

Section: Governing Equations and Dimensionless Groupsmentioning

confidence: 99%

“…Davidson and co-workers (Davidson et al, 2014) concluded that the second one was more satisfactory to represent the electrical potential jump in the interface. Explicit expressions and formulations for the method can be found in (Davidson et al, 2014, Liu et al, 2000.…”

Section: Governing Equations and Dimensionless Groupsmentioning

confidence: 99%

“…The presence of electrolyte solutions may cause the drop interface to carry charge. Davidson and co-workers (Davidson et al, 2014) used an adapted method for capturing interface boundary conditions proposed by Liu and co-workers (Liu et The Journal of Engineering and Exact Sciences -JCEC, Vol. 03 N. 03 (2017) 294-319 al., 2000) to extend the previous numerical model to account for the effect of interfacial charges.…”

Section: Introductionmentioning

confidence: 99%

“…Viscous and electrical forces act on the drop accounting for its behavior regarding the motion inside the channel and the deformation. The model was predicted using a computational fluid dynamic (CFD) numerical model (Berry et al, 2013) that was modified to account for charge density at the drop and liquid interface (Davidson et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Simulation of a Perfect Dielectric Drop in Electro-Osmotic Flow of an Electrolyte Through a Microchannel

Felisberto¹,

Teixeira²

2017

jCEC

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This research uses a computational fluid dynamic model to simulate motion and deformation of a dielectric drop in electrolyte solution in a microchannel. Wall charge density, the Debye-Hückel parameter and the Weber number are varied for uncharged, positively and negatively charged drop interfaces. Drop flow and deformation were analysed and the effects of charge distribution, electric field and permittivity jump were discussed. For a positively charged channel wall, negatively charged drops moved faster and positively charged drops moved slower than an uncharged drop. This effect increased for a higher We. Vortex flow was observed inside the drop. For a low surface tension, the drops were elongated due to electric forces acting on its surface with the charged drops deforming more than the uncharged one. When the permittivity component of the force was removed, the drop had a horizontal deformation that was sufficiently high to cause the negatively charged drop to break up.

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Numerical simulation of two-fluid flow of electrolyte solution with charged deforming interfaces

Davidson

Berry

Pillai

et al. 2016

Applied Mathematical Modelling

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Numerical simulation of the deformation of charged drops of electrolyte

Cited by 3 publications

References 13 publications

Deformation and stability of a viscous electrolyte drop in a uniform electric field

Deformation and stability of a viscous electrolyte drop in a uniform electric field

Simulation of a Perfect Dielectric Drop in Electro-Osmotic Flow of an Electrolyte Through a Microchannel

Numerical simulation of two-fluid flow of electrolyte solution with charged deforming interfaces

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