CFD simulation of equilibrium shape and coalescence of ferrofluid droplets subjected to uniform magnetic field

Ghaffari, Ali; Hashemabadi, Seyed Hassan; Bazmi, Mansour

doi:10.1016/j.colsurfa.2015.04.038

Cited by 40 publications

(35 citation statements)

References 30 publications

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“…5, b is the major axis and a is the minor axis. As shown in this figure, there is a good agreement between the present simulation and the results obtained by Ghaffari et al [36].…”

Section: Deformation Of Static Drop Under Magnetic Fieldsupporting

confidence: 91%

“…In order to examine the accuracy of the current hybrid-algorithm quantitatively, the values of aspect ratio, b/a, at the equilibrium state of ferrofluid droplets for different susceptibilities at Bom = 2.13 were compared by the numerical results of Ghaffari et al [36] in fig. 5, b is the major axis and a is the minor axis.…”

Section: Deformation Of Static Drop Under Magnetic Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Simulation of the co-axial ferrofluid droplets interaction under uniform magnetic field

Ghaderi¹,

Kayhani²,

Nazari³

2019

THERM SCI

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In this study, falling and the coalescence of a pair ferrofluid droplets subjected to uniform magnetic field are investigated numerically. For this approach, a 2-D hybrid approach combined of lattice-Boltzmann and finite volume method is used. The lattice Boltzmann equation with the magnetic force term is solved to update the flow field while the magnetic induction equation is solved using finite volume method to calculate the magnetic field. To validate current simulations, three test cases have been considered: Laplace, multiple rising bubbles and deformation of static drop under magnetic field are analyzed. The comparison of results between the present study and previous researches shows a good agreement. The effects of different parameters: magnetic Bond number, magnetic susceptibility, and magnetic field direction are comprehensively studied. The results show that the coalescence of droplets becomes fast with the increasing Bond number and susceptibility in y-direction magnetic field. Also, the coalescence and falling process of droplets takes more time in the horizontal magnetic field in comparison with the vertical magnetic field.

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“…5, b is the major axis and a is the minor axis. As shown in this figure, there is a good agreement between the present simulation and the results obtained by Ghaffari et al [36].…”

Section: Deformation Of Static Drop Under Magnetic Fieldsupporting

confidence: 91%

Section: Deformation Of Static Drop Under Magnetic Fieldmentioning

confidence: 99%

Simulation of the co-axial ferrofluid droplets interaction under uniform magnetic field

Ghaderi¹,

Kayhani²,

Nazari³

2019

THERM SCI

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show abstract

“…1a). Droplet merging under the influence of a magnetic field is the result of competition between the force due to fluidic pressure (which varies with flow rate ratio), surface tension force and magnetic volume force ( F m )75. Droplet merging will occur if the magnetic volume force exceeds the combined forces due to fluidic pressure and surface tension.…”

Section: Resultsmentioning

confidence: 99%

“…Where, F m is the magnetic volume force, u is velocity, p is pressure, σ is surface tension, κ is curvature and δ s is the smoothed delta function which is zero everywhere except at the interface and ϕ is the level set function687580. The density ρ and viscosity η are defined using the weighted average interpolation, for a volume fraction of the ferrofluid ( = 1 represents DP) by the following equations6869.…”

Section: Discussionmentioning

confidence: 99%

Droplet Merging on a Lab-on-a-Chip Platform by Uniform Magnetic Fields

Varma

Ray

Wang

et al. 2016

Sci Rep

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Droplet microfluidics offers a range of Lab-on-a-chip (LoC) applications. However, wireless and programmable manipulation of such droplets is a challenge. We address this challenge by experimental and modelling studies of uniform magnetic field induced merging of ferrofluid based droplets. Control of droplet velocity and merging was achieved through uniform magnetic field and flow rate ratio. Conditions for droplet merging with respect to droplet velocity were studied. Merging and mixing of colour dye + magnetite composite droplets was demonstrated. Our experimental and numerical results are in good agreement. These studies are useful for wireless and programmable droplet merging as well as mixing relevant to biosensing, bioassay, microfluidic-based synthesis, reaction kinetics, and magnetochemistry.

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“…The disadvantage of this particle-based method is its high computational demand, which was discussed above. In other papers the nanoparticle aggregation is investigated with continuum-based approaches, enabling one to simulate the particle suspensions [16,17]. It should be noted that in these continuum-based works, although the force of the external magnetic field on the particles is taken into account, the particle-particle magnetic interactions are not investigated, which can be a relevant phenomenon during the MNP aggregation.…”

Section: Introductionmentioning

confidence: 99%

Investigation and Modeling of the Magnetic Nanoparticle Aggregation with a Two-Phase CFD Model

2020

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In this paper the magnetic nanoparticle aggregation procedure in a microchannel in the presence of external magnetic field is investigated. The main goal of the work was to establish a numerical model, capable of predicting the shape of the nanoparticle aggregate in a magnetic field without extreme computational demands. To that end, a specialized two-phase CFD model and solver has been created with the open source CFD software OpenFOAM. The model relies on the supposed microstucture of the aggregate consisting of particle chains parallel to the magnetic field. First, the microstructure was investigated with a micro-domain model. Based on the theoretical model of the particle chain and the results of the micro-domain model, a two-phase CFD model and solver were created. After this, the nanoparticle aggregation in a microchannel in the field of a magnet was modeled with the solver at different flow rates. Measurements with a microfluidic device were performed to verify the simulation results. The impact of the aggregate on the channel heat transfer was also investigated.

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CFD simulation of equilibrium shape and coalescence of ferrofluid droplets subjected to uniform magnetic field

Cited by 40 publications

References 30 publications

Simulation of the co-axial ferrofluid droplets interaction under uniform magnetic field

Simulation of the co-axial ferrofluid droplets interaction under uniform magnetic field

Droplet Merging on a Lab-on-a-Chip Platform by Uniform Magnetic Fields

Investigation and Modeling of the Magnetic Nanoparticle Aggregation with a Two-Phase CFD Model

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