Numerical investigation of the drag closure for bubbles in bubble swarms

Lau, YM Yuk Man; Roghair, I.; Deen, NG Niels; Annaland, van M Martin Sint; Kuipers, J.A.M.

doi:10.1016/j.ces.2011.01.053

Cited by 29 publications

(11 citation statements)

References 16 publications

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“…Several studies were conducted to investigate the relationship between these two drag coefficients; according to their results, as gas holdup increases the ratio between C D and C D,1 rises, but for small holdups this ratio approaches unity [49,50]. The values of overall gas holdup for the air/water system and all of the air/activated sludge systems were experimentally measured in our previous study and the range of their variations was 0.001-0.032 [26].…”

Section: Analysis Of Bubble Characteristics Based On Dgd Techniquementioning

confidence: 97%

Analysis of gas phase characteristics and mixing performance in an activated sludge bioreactor using electrical resistance tomography

Babaei

Bonakdarpour

Ein‐Mozaffari

2015

Chemical Engineering Journal

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Section: Analysis Of Bubble Characteristics Based On Dgd Techniquementioning

confidence: 97%

Analysis of gas phase characteristics and mixing performance in an activated sludge bioreactor using electrical resistance tomography

Babaei

Bonakdarpour

Ein‐Mozaffari

2015

Chemical Engineering Journal

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“…for the drag force) have successfully been applied in a larger scale discrete bubble model (Lau et al, 2011) following the multi-scale modelling strategy (van Sint Annaland et al, 2003). However, it is also possible to adopt this approach for investigation of interfacial mass transfer phenomena in dense bubbly flows.…”

Section: Mass Transfermentioning

confidence: 98%

An improved Front-Tracking technique for the simulation of mass transfer in dense bubbly flows

Roghair

Annaland

Kuipers

2016

Chemical Engineering Science

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“…Using small scale, highly detailed direct numerical simulations (DNS), the forces acting on gas bubbles rising through a liquid can be described in a very accurate manner. These insights and correlations of these forces are used again in larger scale, but more coarsely resolved, models such as a discrete element method …”

Section: Introductionmentioning

confidence: 99%

“…An accurate description of the drag force experienced by bubbles rising in a swarm is crucial, because the residence time of bubbles in a bubble column reactor (and hence the efficiency of the process) is dominated by the drag force. It is, therefore, of major importance for large‐scale numerical modeling, for instance, in application in Euler–Lagrange modeling techniques such as performed by Lau et al…”

Section: Introductionmentioning

confidence: 99%

Drag force and clustering in bubble swarms

2012

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In this article, results of detailed numerical simulations are reported meant to provide a closure relation for the drag force acting on bubbles rising in a dense swarm. The formation of clusters of bubbles in a periodic domain and the effect thereof on the rise velocity and effective drag coefficient on the bubbles are studied. Using smaller bubble sizes than presented in our earlier work, we are also able to refine our correlation for the drag coefficient acting on bubbles rising in a swarm, such that it is applicable for a large range of bubble sizes. The simulations are performed with an advanced Front‐Tracking model in which Lagrangian marker points are used to track the gas–liquid interface, while accounting for surface tension and substantial interface deformation. Simulations were performed using periodic domains to simulate rising air bubbles in water from 1.0 mm up to 6.0 mm in diameter. The effect of liquid phase viscosity was also studied to extend the range of validity of the drag correlation. For the 1.0 and 1.5 mm cases, strong horizontal clustering effects are observed. Especially, at high gas fractions, the bubbles tend to form rigid horizontal arrays, which have been shown to strongly increase the drag force acting on the bubbles in the cluster. For viscous liquids, the tendency to form horizontal clusters is lower, and even vertical clustering is observed. The bubble slip velocity was compared with the experimental results of Zenit et al., which agree very well taking into account the differences between simulations and experiments. Based on our simulations, a new drag correlation was proposed, taking into account Eötvös numbers ranging from 0.13 to 4.9, and Morton numbers in the range 3.8 ≤ − log Mo < 6.6, and gas hold‐ups up to 40% (30% for Eo < 0.3). At lower values for −log Mo, the Reynolds number drops to the order of unity, and the correlation overpredicts the drag coefficient, which defines the range of applicability of the currently proposed drag correlation. The correlation itself describes a linear increase of the normalized drag coefficient as a function of the gas hold‐up. The strength of linear increase is stronger at lower Eötvös numbers. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1791–1800, 2013

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Numerical investigation of the drag closure for bubbles in bubble swarms

Cited by 29 publications

References 16 publications

Analysis of gas phase characteristics and mixing performance in an activated sludge bioreactor using electrical resistance tomography

Analysis of gas phase characteristics and mixing performance in an activated sludge bioreactor using electrical resistance tomography

An improved Front-Tracking technique for the simulation of mass transfer in dense bubbly flows

Drag force and clustering in bubble swarms

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