Studies of plug formation in microchannel liquid–liquid flows using advanced particle image velocimetry techniques

Chinaud, Maxime; Roumpea, Eyangelia-Panagiota; Angeli, Panagiota

doi:10.1016/j.expthermflusci.2015.07.022

Cited by 21 publications

(10 citation statements)

References 41 publications

(40 reference statements)

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“…The correlation peak position was computed with Gaussian peak algorithm detection and the validation of the velocity vectors was based on standard deviation and primary to secondary peak vectors. Removed false vectors were replaced with the median value of neighboring velocity vectors (Chinaud et al, 2015).…”

Section: Experimental Apparatusmentioning

confidence: 99%

Intensified Eu(III) extraction using ionic liquids in small channels

Angeli

2016

Chemical Engineering Science

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The extraction of Eu(III) from nitric acid solutions was studied in intensified small scale separation units using an ionic liquid solution (0.2M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyphosphine oxide (CMPO)-1.2M Tributylphosphate) (TBP)/1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide; ([C4min][NTf2])as the extraction phase. The investigations were carried out in channels with 0.2 mm and 0.5 mm diameter for phase flowrates that result in plug flow with the aqueous solution as the dispersed phase. The interfacial area in plug flow and the velocity profiles within the plugs were studied with high speed imaging and bright field micro Particle Image Velocimetry. Distribution and mass transfer coefficients were found to have maximum values at nitric acid concentration of 1M. Mass transfer coefficients were higher in the small channel, where recirculation within the plugs and interfacial area are large, compared to the large channel for the same mixture velocities and phase flow rates. Within the same channel, mass transfer coefficients decreased with increasing residence time indicating that significant mass transfer takes place at the channel inlet where the two phases come into contact. The experimental results were compared with previous correlations on mass transfer coefficients in plug flows.

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Section: Experimental Apparatusmentioning

confidence: 99%

Intensified Eu(III) extraction using ionic liquids in small channels

Angeli

2016

Chemical Engineering Science

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“…Tsaoulidis and Angeli 22 used an image acquisition system based on bright field PIV to visualize film thickness and recirculation patterns in liquid plugs at small channels of varying size. Chinaud et al 23 obtained velocity profiles within both liquid phases during plug breakage at the T-junction inlet of a microchannel using a two-color mPIV technique.…”

Section: Flowsmentioning

confidence: 99%

“…23 Two types of tracer particles with different fluorescing wavelengths were dispersed, each in one phase. The aqueous phase was seeded with 1-lm carboxylate-modified microspheres FluoSpheres V R with orange fluorescent colour (540/560 nm) at a volume ratio of 0.04.…”

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confidence: 99%

Experimental investigations of non‐Newtonian/Newtonian liquid‐liquid flows in microchannels

2017

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The plug flow of a non-Newtonian and a Newtonian liquid was experimentally investigated in a quartz microchannel (200-mm internal diameter). Two aqueous glycerol solutions containing xanthan gum at 1000 and 2000 ppm were the non-Newtonian fluids and 0.0046 Pa s silicone oil was the Newtonian phase forming the dispersed plugs. Two-color particle image velocimetry was used to obtain the hydrodynamic characteristics and the velocity profiles in both phases under different fluid flow rates. The experimental results revealed that the increase in xanthan gum concentration produced longer, bullet-shaped plugs, and increased the thickness of the film surrounding them. From the shear rate and viscosity profiles, it was found that the polymer solution was in the shear-thinning region while the viscosity was higher in the middle of the channel compared to the region close to the wall. Circulation times in the aqueous phase increased with the concentration of xanthan gum.

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“…The focal plane was placed in the center of the channel. Velocity fields during coalescence were acquired with a high-speed shadowgraphy system [32]. In this technique, the channel is illuminated with a uniform white backlight and images of the tracer particles added in the aqueous phase are recorded by the high-speed camera placed in front of it.…”

Section: -3mentioning

confidence: 99%

“…High-magnification shadowgraphy measurements can be conducted with a constant LED backlight source for volumetric illumination. The measurement volume is then defined by the focal plane and the depth of field of the imaging system, which is smaller than the cell depth but of the same order of magnitude, while the time resolution is only limited by the acquisition frequency of the camera [32].…”

Section: Introductionmentioning

confidence: 99%

Surfactant effects on the coalescence of a drop in a Hele-Shaw cell

2016

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In this work the coalescence of an aqueous drop with a flat aqueous-organic interface was investigated in a thin gap Hele-Shaw cell. Different concentrations of a nonionic surfactant (Span 80) dissolved in the organic phase were studied. We present experimental results on the velocity field inside a coalescing droplet in the presence of surfactants. The evolution of the neck between the drop and the interface was studied with high-speed imaging. It was found that the time evolution of the neck at the initial stages of coalescence follows a linear trend, which suggests that the local surfactant concentration at the neck region for this stage of coalescence can be considered quasiconstant in time. This neck expansion can be described by the linear law developed for pure systems when the surfactant concentration at the neck is assumed higher than in the bulk solution. In addition, velocity and vorticity fields were computed inside the coalescing droplet and the bulk homophase using a high-speed shadowgraphy technique. The significant wall effects in the Hele-Shaw cell in the transverse axis cause the two vertical velocity components towards the singularity rupture point, from the drop and from the bulk homophase, to be of the same order of magnitude. This movement together with the neck expansion creates two pairs of counteracting vortices in the drop and in the bulk phase. The neck velocity is the average of the advection velocities of the two counteracting vortex pairs on each side of the neck. The presence of the surfactant slows down the dynamics of the coalescence, affects the propagation direction of the pair of vortices in the bulk phase, and reduces their size faster compared to the system without surfactant.

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Studies of plug formation in microchannel liquid–liquid flows using advanced particle image velocimetry techniques

Cited by 21 publications

References 41 publications

Intensified Eu(III) extraction using ionic liquids in small channels

Intensified Eu(III) extraction using ionic liquids in small channels

Experimental investigations of non‐Newtonian/Newtonian liquid‐liquid flows in microchannels

Surfactant effects on the coalescence of a drop in a Hele-Shaw cell

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