Computational fluid dynamics modeling of gas dispersion in multi impeller bioreactor

Ahmed, Syed Ubaid; Ranganathan, Panneerselvam; Pandey, Ashok; Savithri, S.

doi:10.1016/j.jbiosc.2009.11.014

Cited by 65 publications

(24 citation statements)

References 20 publications

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“…5). Similar behaviour of this model we can see also in the results published by Ahmed et al (2010). The approach proposed by Bakker is based on modification of the Reynolds number.…”

Section: Gas Hold-upsupporting

confidence: 85%

See 1 more Smart Citation

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

Kálal¹,

Jahoda²,

Fořt³

2014

Chemical and Process Engineering

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The main topic of this study is the experimental measurement and mathematical modelling of global gas hold-up and bubble size distribution in an aerated stirred vessel using the population balance method. The air-water system consisted of a mixing tank of diameter T = 0.29 m, which was equipped with a six-bladed Rushton turbine. Calculations were performed with CFD software CFX 14.5. Turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the homogeneous MUSIG method with 24 bubble size groups. To achieve a better prediction of the turbulent quantities, simulations were performed with much finer meshes than those that have been adopted so far for bubble size distribution modelling. Several different drag coefficient correlations were implemented in the solver, and their influence on the results was studied. Turbulent drag correction to reduce the bubble slip velocity proved to be essential to achieve agreement of the simulated gas distribution with experiments. To model the disintegration of bubbles, the widely adopted breakup model by Luo & Svendsen was used. However, its applicability was questioned.

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“…5). Similar behaviour of this model we can see also in the results published by Ahmed et al (2010). The approach proposed by Bakker is based on modification of the Reynolds number.…”

Section: Gas Hold-upsupporting

confidence: 85%

“…The most frequently used breakup model was given by Luo and Svendsen (1996). It has been applied by many authors for modelling of the BSD in stirred tanks (e.g., Ahmed et al, 2010;Kerdouss et al, 2008;Montante et al, 2008;Ranganathan and Sivaraman, 2011;Selma et al, 2010). Therefore, we focus on reviewing this breakup model in our work.…”

Section: Introductionmentioning

confidence: 99%

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

Kálal¹,

Jahoda²,

Fořt³

2014

Chemical and Process Engineering

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“…A representative estimate of turbulence has been found recently based on the work of Kawase et al (7). These authors recommend evaluation of the superficial oxygen transfer coefficient, k L relative to the rate of turbulent kinetic energy dissipation ε, as follows from the equation: (1) [Pa•s] are the density and the viscosity of the continuous aqueous phase, L. these parameters impose the effect of motion by ε and h L and allow the study of the effect of fluid flow on the mass transfer during bioreaction. Based on broth similar conditions, coefficient C 1 = 0.3 was assumed from reference (9).…”

Section: Resultsmentioning

confidence: 99%

“…Recent literature on biotechnology reveals numerous cases of bioreactions that require high dissolved oxygen tension in order to obtain higher yields in shorter fermentation time (1,13). Our own measurements of bioproduction rates of exopolysaccharides have shown an increase of up to 40% in the bioproduction by the species Aerobacillus palidus depending on the oxygen transfer rate (OTR) and stagnancy elimination (15).…”

Section: Introductionmentioning

confidence: 99%

Bioprocess Improvement by Design-Modified Bioreactor Flow Properties

Georgiev¹,

Vlaev²

2012

Biotechnology & Biotechnological Equipment

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“…The most frequently used breakup model was derived by Luo and Svendsen (1996). It has been applied by many authors for modelling the BSD in stirred tanks (e.g., Ahmed et al, 2010;Kerdouss et al, 2008;Montante et al, 2008;Ranganathan and Sivaraman, 2011;Selma et al, 2010); other models have seldom been applied (Gimbun et al, 2009;Laakkonen et al, 2007). The model by Luo & Svendsen was introduced in our previous work (Kálal et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Modelling of the Bubble Size Distribution in an Aerated Stirred Tank: Theoretical and Numerical Comparison of Different Breakup Models

Kálal¹,

Jahoda²,

Fořt³

2014

Chemical and Process Engineering

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The main topic of this study is the mathematical modelling of bubble size distributions in an aerated stirred tank using the population balance method. The air-water system consisted of a fully baffled vessel with a diameter of 0.29 m, which was equipped with a six-bladed Rushton turbine. The secondary phase was introduced through a ring sparger situated under the impeller. Calculations were performed with the CFD software CFX 14.5. The turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the MUSIG method with 24 bubble size groups. For the bubble size distribution modelling, the breakup model by Luo and Svendsen (1996) typically has been used in the past. However, this breakup model was thoroughly reviewed and its practical applicability was questioned. Therefore, three different breakup models by Martínez-Bazán et al. (1999a, b), Lehr et al. (2002) and Alopaeus et al. (2002) were implemented in the CFD solver and applied to the system. The resulting Sauter mean diameters and local bubble size distributions were compared with experimental data.

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Computational fluid dynamics modeling of gas dispersion in multi impeller bioreactor

Cited by 65 publications

References 20 publications

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

Bioprocess Improvement by Design-Modified Bioreactor Flow Properties

Modelling of the Bubble Size Distribution in an Aerated Stirred Tank: Theoretical and Numerical Comparison of Different Breakup Models

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