Effective-medium theories for predicting hydrodynamic transport properties of bidisperse suspensions

Koo, Sangkyun; Sangani, Ashok S.

doi:10.1063/1.1503352

Cited by 13 publications

(13 citation statements)

References 23 publications

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“…As pointed out by Dodd et al [35], the above choice of R is necessary to ensure that the conditionally averaged field has the correct behavior at large distances from the test particle for the problem of determining the averaged diffusivity of integral membrane proteins. Subsequent studies showed that the above choice also yields excellent estimates of the effective properties even when it has no rigorous basis (as e.g., see [33,39]). Random suspensions with a hardsphere potential have a non-zero S(0) even in the dilute limit, which is accurately given by the Carnahan-Starling approximation [40] as: ( )…”

Section: Figurementioning

confidence: 99%

Effective permittivity of dense random particulate plasmonic composites

2012

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An effective-medium theory (EMT) is developed to predict the effective permittivity ε eff of dense random dispersions of high optical-conductivity metals such as Ag, Au, and Cu. Dependence of ε eff on the volume fraction ϕ, a microstructure parameter κ related to the static structure factor and particle radius a, is studied. In the electrostatic limit, the upper and lower bounds of κ correspond to Maxwell-Garnett and Bruggeman EMTs, respectively. Finite size effects are significant when jβ 2 ka∕n 3 j becomes O1, where β, k, and n denote the nanoparticle polarizability, wavenumber, and matrix refractive index, respectively. The coupling between the particle and effective medium results in a red-shift in the resonance peak, a nonlinear dependence of ε eff on ϕ, and Fano resonance in ε eff .

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Section: Figurementioning

confidence: 99%

Effective permittivity of dense random particulate plasmonic composites

2012

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“…The effect of non-Newtonian flow and volume fraction / is included. This assumption agrees with the effective-medium theory (Koo and Sangani 2002), which uses models from force analysis to estimate conditionally averaged fields and, hence, the effective properties of dispersed particles and the carrier fluid. This assumption is extended to the simulation of the microscopic fluid region near the forming droplets, where the effect of other existing droplets is taken into account in the effective property while only the forming droplets from the aperture are included in NS equation solution.…”

Section: Introductionmentioning

confidence: 52%

Micro-droplet formation in non-Newtonian fluid in a microchannel

Qiu¹,

Silva²,

Tonkovich³

et al. 2009

Microfluid Nanofluid

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Micro-droplet formation from an aperture with a diameter of micrometers is numerically investigated under the cross-flow conditions of an experimental microchannel emulsification process. The process involves dispersing an oil phase into continuous phase fluid through a microchannel wall made of apertured substrate. Crossflow in the microchannel is of non-Newtonian nature, which is included in the simulations. Micro-droplets of diameter 0.76-30 lm are obtained from the simulations for the apertures of diameter 0.1-10.0 lm. The simulation results show that rheology of the bulk liquid flow greatly affects the formation and size of droplets and that dispersed micro-droplets are formed by two different breakup mechanisms: in dripping regime and in jetting regime characterized by capillary number Ca. Relations between droplet size, aperture opening size, interfacial tension, bulk flow rheology, and disperse phase flow rate are discussed based on the simulation and the experimental results. Data and models from literature on membrane emulsification and T-junction droplet formation processes are discussed and compared with the present results. Detailed force balance models are discussed. Scaling factor for predicting droplet size is suggested.

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“…The modification was, however, turned out to overpredict the sedimentation velocity. Although some numerical investigations have been performed on the bidisperse suspensions [13,14], a simple and accurate method which theoretically estimates the sedimentation velocity has seldom been presented.…”

Section: Introductionmentioning

confidence: 99%