Fluid dynamics and mass transfer at single droplets in liquid/liquid systems

Wegener, M.; Paul, N.; Kraume, Matthias

doi:10.1016/j.ijheatmasstransfer.2013.12.024

Cited by 141 publications

(120 citation statements)

References 74 publications

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“…The estimated value of the coefficient a 1 is 0.35. This is smaller than the minimum 0.857 noted by Wegener et al [5] which confirms that in addition to diffusion there are other phenomena…”

Section: Droplet Formationsupporting

confidence: 58%

“…The model is based on assumption that the mass transfer process is diffusion controlled so interfacial instabilities and internal circulation is not taken into account. The constant a 1 varies between 0.857 and 3.43 [5].…”

Section: Mass Transfer In Droplet Formationmentioning

confidence: 99%

“…In traditional experiments a droplet concentration are measured before formation and after coalescence and this provides an overall mass transfer rates for all stages. By using suitable experimental arrangements the effect of coalescence can be minimized but the droplet formation stage is often substantial [2][3][4][5] and by using several different droplet rise times the effect of formation is found by extrapolation of results into zero rise time.…”

Section: Introductionmentioning

confidence: 99%

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Modeling Mass Transfer During Single Organic Droplet Formation and Rise

Lahdenperä¹

2017

J Chem Eng Process Technol

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Copper reactive extraction from ambient aqueous solution to organic droplets using single droplet experiments was performed. Extractant was Agorca M5640 hydroxyoxime in Exxsol D80. An image analysis based method was used to determine droplet concentration directly after droplet formation and rise. Mass transfer during formation is correlated using literature. Level Set interface tracking method was used to find formation hydrodynamics and as a result the assumption of non-circular velocity field could be validated. This was also supported by the circulation criteria based on needle Reynolds number. A model to estimate extraction rate as function of droplet Fourier number was based on a literature correlation and it was found that a model where the interface effect was described using interface mobility parameter was able to predict satisfactorily mass transfer. For a rising droplet stagnant cap model was used. Stagnant cap volumes were estimated from droplet images. A CFD model of a non-deforming rising droplet with rigid interface was used to fit interfacial reaction kinetic constant. Fitted value was much lower than experimentally determined by high a shear reactor. Mass transfer coefficients calculated from CFD model and estimated using literature correlations agreed well. By applying a two-film model it was shown that major part of the resistance is located at the interface between the phases.

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Section: Droplet Formationsupporting

confidence: 58%

Section: Mass Transfer In Droplet Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling Mass Transfer During Single Organic Droplet Formation and Rise

Lahdenperä¹

2017

J Chem Eng Process Technol

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“…Based on these researches, fluid dynamics and mass transfer are inseparably linked with interfacial properties and the associated interfacial phenomena, such as deformation, oscillation, Marangoni instabilities, surfactant ad-or desorption, and so forth. [46][47][48] Recently, some researchers have initiated evaluating the effect of nanoparticles on liquid-liquid extraction process. Bahmanyar et al 13 investigated mass-transfer performance and hydrodynamic characteristics of kerosene-based SiO 2 nanofluids in a pulsed liquid-liquid extraction column.…”

Section: Introductionmentioning

confidence: 99%

Mass transfer into/from nanofluid drops in a spray liquid‐liquid extraction column

Ashrafmansouri

Esfahany

2015

AIChE Journal

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The performance of a spray liquid-liquid extraction column at two mass-transfer directions was experimentally studied in the presence of silica nanoparticles. Toluene-based nanofluid drops containing 0.0005-0.01 vol % silica nanoparticles were dispersed in aqueous phase and acetic acid (AA) transfer between phases was investigated. The experiments were performed at fixed volumetric flow rates of dispersed and continuous phases. Maximum enhancement of 47.4% and 107.5% in overall mass-transfer coefficient, respectively, for mass-transfer direction of dispersed to continuous phase and vice versa were achieved for drops with 0.001 vol % silica nanoparticles. These enhancements can be referred to Brownian motion of nanoparticles and induced microconvection. The results showed that nanoparticles are more effective in augmenting AA transfer from continuous to dispersed phase. Probable reason is that smaller diameter and lower internal turbulence of drops in this transfer direction increase dispersed phase resistance potential to be manipulated by Brownian motion of nanoparticles.

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“…The rising path of droplets is analysed because most critical impurities alter the surface mobility and, therefore, the drag coefficient and the rising velocity. The drop rise velocity was determined as described in Villwock et al [9] and compared to the theoretical trajectory of a drop with fully mobile interface [16,17].…”

Section: Experimental Set-upmentioning

confidence: 99%

Automated image analysis for trajectory determination of single drop collisions

Kamp

Hänsch

Kendzierski

et al. 2016

Computers & Chemical Engineering

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The fundamental analysis of drop coalescence probability in liquid/liquid systems is necessary to reliably predict drop size distributions in technical applications. For this crucial investigation two colliding oil drops in continuous water phase were recorded with different high speed camera set-ups under varying conditions. In order to analyse the huge amount of recorded image sequences with varying resolutions and qualities, a robust automated image analysis was developed. This analysis is able to determine the trajectories of two colliding drops as well as the important events of drop detachment from cannulas and their collision. With this information the drop velocity in each sequence is calculated and mean values of multiple drop collisions are determined for serial examinations of single drop collisions. Using the developed automated image analysis for drop trajectory and velocity calculation, approximately 1-2 recorded high speed image sequences can be evaluated per minute.

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Fluid dynamics and mass transfer at single droplets in liquid/liquid systems

Cited by 141 publications

References 74 publications

Modeling Mass Transfer During Single Organic Droplet Formation and Rise

Modeling Mass Transfer During Single Organic Droplet Formation and Rise

Mass transfer into/from nanofluid drops in a spray liquid‐liquid extraction column

Automated image analysis for trajectory determination of single drop collisions

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