Mass transfer and chemical reactions in bubble swarms with dynamic interfaces

Koynov, Athanas; Khinast, Johannes G.; Tryggvason, Grétar

doi:10.1002/aic.10529

Cited by 110 publications

(73 citation statements)

References 57 publications

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“…As an example, using front tracking and volume of fluid models, Dijkhuizen et al [4] obtained hydrodynamic (drag, lift and virtual mass) closures and found good agreement with experimental data reported in the literature. Furthermore, based on two-dimensional front tracking modeling with additional mass balance equations, Koynov et al [7] showed that the mass transfer coefficient can also be extracted from such detailed numerical simulations.…”

Section: Introductionmentioning

confidence: 98%

Detailed 3D Modeling of Mass Transfer Processes in Two‐Phase Flows with Dynamic Interfaces

2006

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A model is presented which allows a priori computation of mass transfer coefficients for bubbles (droplets) rising in quiescent Newtonian fluids. The proposed model is based on the front tracking technique and explicitly accounts for the bubble-liquid mass transfer process. The dissolved species concentration in the liquid phase is computed from a species conservation equation while the value of the concentration at the interface is imposed via an immersed boundary technique. Simulations are carried out to demonstrate the capabilities of the model to predict bubble shape, flow field as well as transport of a species from the bubble to the liquid phase.

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Section: Introductionmentioning

confidence: 98%

Detailed 3D Modeling of Mass Transfer Processes in Two‐Phase Flows with Dynamic Interfaces

2006

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“…For example, we examined cases, where small and large bubbles yield high selectivity, while intermediate bubbles led to a selectivity reduction of more than 10 %, a significant amount. Interested readers are referred to [19][20][21][22]. In most industrially relevant systems, high gas holdup leads to bubbles rising together in close proximity.…”

Section: Flow and Mixing -Bubble/droplet Swarmsmentioning

confidence: 99%

Micromixing in Reactive, Deformable Bubble and Droplet Swarms

Koynov

Khinast

2006

Chem Eng & Technol

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Detailed, high-resolution numerical simulations have been performed of the buoyancy-driven motion of deformable, chemically reacting bubble and droplet swarms. Mass transfer rates and chemical reaction selectivities were determined and a comparison is presented between the results for bubble/droplet swarms and single bubbles. The mixing in the wake of bubbles was characterized as well. It was shown that for mixing-sensitive reaction networks, the hydrodynamics of the bubble swarm may significantly impact the reaction selectivity. Four special cases are highlighted, i.e., highly exothermic reactions, heterogeneously catalyzed reactions, animal cell cultures and experiments. The most important outcome of this work is that bubble swarms and the impact of the swarm hydrodynamics on reacting systems can be studied in detail. This is the first study of this kind reported in the literature. Its importance is paramount as knowledge of the unique flow dynamics inside bubble swarms is crucial to understanding the mechanisms controlling mass transport and chemical reactions and is a prerequisite for effective process intensification.

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“…The three different wake structures affect the yields and selectivity of mixing-sensitive chemical reactions. The swarm influence on chemical reactions was studied in Koynov et al [18], while a significant influence on the reaction selectivity could be observed for mixing sensitive reactions. Nevertheless, the simulations were case studies and a direct validation with experimental data is missing.…”

Section: Introductionmentioning

confidence: 99%

Reactive Mass Transfer of Single NO Bubbles and Bubble Bouncing in Aqueous Ferric Solutions – A Feasibility Study

Hlawitschka

Oßberger

Backes

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-Reactive bubble columns are widely used in the chemical, petrochemical, biochemical and metal industries. While the reactive mass transfer around a single spherical shaped bubble is quite well described in literature, the influence of hydrodynamic interactions, such as bubble bouncing or coalescence on mass transfer -with and without chemical reaction -is not well understood. As to this, high resolution simulations and sophisticated experimental analysis based on high-speed camera images and local color changes gives a new firm basis. In this work, a new system is presented, based on Nitric Oxide (NO) gas absorbed in a Fe II -solution. The reaction rate can be adjusted by the addition of ligands and the resulting local color change is detected. The impact of the colliding bubbles leads to a deformation of the bubble shapes and creates a fast movement of the bubble interfaces, which, finally, leads to an increased mass transfer. The results of five tested ligands reveal the high potential of the reactive Fe II (NO) system to investigate basic phenomena affecting yield and selectivity of mixing-sensitive chemical reactions.Résumé -Transfert de masse réactive de bulles simples et de bulles rebondissantes dans les solutions ferriques aqueuses -Une étude de faisabilité -Les colonnes à bulles réactives sont largement utilisées dans les industries chimiques, pétrochimiques, biochimiques et métalliques. Bien que le transfert de masse réactif autour d'une seule bulle de forme sphérique soit assez bien décrit dans la littérature, l'influence des interactions hydrodynamiques, comme le rebond des bulles ou la coalescence sur le transfert de masse -avec ou sans réaction chimique -n'est pas bien comprise. Pour ce faire, des simulations de haute résolution et des analyses expérimentales sophistiquées basées sur des images de caméras à haute vitesse et des changements de couleur locaux donnent une nouvelle base solide. Dans ce travail, un nouveau système est présenté, basé sur l'oxyde nitrique (NO) gazeux absorbé dans une solution de Fe II . La vitesse de réaction peut être ajustée par addition de ligands et le changement de couleur local résultant est détecté. L'impact des bulles de collision entraîne une déformation des formes de bulles et crée un mouvement rapide des interfaces de bulles, ce qui conduit finalement à un transfert de masse accru. Les résultats de cinq ligands testés révèlent le haut potentiel du système réactif Fe II (NO) pour étudier les phénomènes fondamentaux affectant le rendement et la sélectivité des réactions chimiques sensibles au mélange.

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Mass transfer and chemical reactions in bubble swarms with dynamic interfaces

Cited by 110 publications

References 57 publications

Detailed 3D Modeling of Mass Transfer Processes in Two‐Phase Flows with Dynamic Interfaces

Detailed 3D Modeling of Mass Transfer Processes in Two‐Phase Flows with Dynamic Interfaces

Micromixing in Reactive, Deformable Bubble and Droplet Swarms

Reactive Mass Transfer of Single NO Bubbles and Bubble Bouncing in Aqueous Ferric Solutions – A Feasibility Study

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