From single drop coalescence to droplet swarms – Scale-up considering the influence of collision velocity and drop size on coalescence probability

Kamp, Johannes; Kraume, Matthias

doi:10.1016/j.ces.2016.08.028

Cited by 25 publications

(26 citation statements)

References 53 publications

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“…A variety of models to describe coalescence have been proposed, for which recent extensive overviews are available , , , . Here, only those aspects relevant for this work are summarized.…”

Section: Different Principal Approaches To Describe Coalescencesupporting

confidence: 59%

“…has to be extended for an additional effect observed experimentally. Kamp as well as Lehr and Mewes evaluated the coalescence probability between individual drops and bubbles, respectively. The authors found that for high relative velocity the coalescence probability is close to zero.…”

Section: Coalescence Model Adapted For Technical Equipmentmentioning

confidence: 89%

“…To investigate, which model is better suited to describe coalescence, Kamp performed collision experiments between one fixed drop and a moving drop and found that for high relative velocity, the coalescence probability is close to zero . This cannot be described with the energy model, which is thus not applicable for liquid dispersions.…”

Section: Different Principal Approaches To Describe Coalescencementioning

confidence: 99%

“…The coalescence frequency is thus frequently described as the product of collision frequency and coalescence probability , :

true f_{normalcoalescence} = f_{normalcollision} p_{normalcoalescence}

…”

Section: Coalescence Model Adapted For Technical Equipmentmentioning

confidence: 99%

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Coalescence Modeling for Design of Technical Equipment

Leleu

Pfennig

2019

Chem Eng & Technol

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A coalescence model in the context of the ReDrop concept (Representative Drops) is proposed to design technical equipment for separating liquid-liquid dispersions in settlers or extraction columns. A fundamental study of drop interactions has been performed to obtain the complete picture of coalescence. The model proposed accounts for collision frequency of the drops, bouncing probability, and coalescence probability, for which the film-drainage approach is applied. The model proposed allows considering the appropriate formulation for different types of equipment. Especially noteworthy is that the coalescence probability fundamentally differs from the expression of Coulaloglou and Tavlarides, which is frequently used, but which shows inconsistencies at fundamental level.Batch settling experiments have been performed to validate the numerical approach and thus the coalescence model. The

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“…A variety of models to describe coalescence have been proposed, for which recent extensive overviews are available , , , . Here, only those aspects relevant for this work are summarized.…”

Section: Different Principal Approaches To Describe Coalescencesupporting

confidence: 59%

Section: Coalescence Model Adapted For Technical Equipmentmentioning

confidence: 89%

Section: Different Principal Approaches To Describe Coalescencementioning

confidence: 99%

“…The coalescence frequency is thus frequently described as the product of collision frequency and coalescence probability , :

true f_{normalcoalescence} = f_{normalcollision} p_{normalcoalescence}

…”

Section: Coalescence Model Adapted For Technical Equipmentmentioning

confidence: 99%

See 2 more Smart Citations

Coalescence Modeling for Design of Technical Equipment

Leleu

Pfennig

2019

Chem Eng & Technol

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“…The development of combined CFD/PBE models has provided unprecedented insight into the fundamentals of bubbly flows . Population balance models give a realistic representation of the behavior of the bubbles and phase interfaces, while CFD provides local information regarding flow and liquid phase turbulence . The population balance models do contain a number of correlations based on experimental observations, such as semiempirically derived models for bubble coalescence and break‐up.…”

Section: Introductionmentioning

confidence: 99%

Prediction of gas density effects on bubbly flow hydrodynamics: New insights through an approach combining population balance models and computational fluid dynamics

et al. 2018

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Detailed measurements and computational fluid dynamics (CFD) investigation of the hydrodynamics in a bubble column containing internal features causing flow disturbances are presented for both air and helium gases. An optical needle probe has been used to measure profiles of bubble size, bubble velocity, and gas holdup at different locations across the cross section of the column. An approach combining CFD with population balances is able to represent observed multiphase flow phenomena such as the effect of the pipes to remix and redistribute the gas as well as the tendency of the gas to channel through a slit in the pipes rather than go around the pipes. The comparison of CFD simulation to experimental measurements reveal that the overall decrease in gas holdup observed when switching from air to helium gas can be explained by swarm effects, whereas the steeper decrease in the gas holdup profile across the column is due to coalescence effects. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3764–3774, 2018

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On the role of the macroscopic deformation in liquid film drainage between bubbles

Song

Zhang

et al. 2023

AIChE Journal

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The collision of bubbles in multiphase reactors is critical to bubble size distribution. However, the theoretical models that can reasonably predict collision outcomes and the experimental data that can be used to directly verify the models are still very lacking. We studied the collision of two bubbles in clean water through experiments and theoretical modeling, revealing the mechanism that the collision result shifts from coalescence to rebound with increasing collision velocity. The macroscopic deformation (MacrD) of bubbles is associated with the film drainage via a segmented linear equation as a function of the film radius and initial Weber number. Thus, the current model can reflect the effect of MacrD in a self‐consistent way. The coalescence times and critical coalescence velocities predicted by the model were in good agreement with the experiments. This work provides novel insights into bubble coalescence modeling and serves to improve the accuracy of reactor simulations.

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From single drop coalescence to droplet swarms – Scale-up considering the influence of collision velocity and drop size on coalescence probability

Cited by 25 publications

References 53 publications

Coalescence Modeling for Design of Technical Equipment

Coalescence Modeling for Design of Technical Equipment

Prediction of gas density effects on bubbly flow hydrodynamics: New insights through an approach combining population balance models and computational fluid dynamics

On the role of the macroscopic deformation in liquid film drainage between bubbles

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