Detailed investigations of the multiphase flow in airlift tower loop reactors

Lübbert, Α.; Larson, B.

doi:10.1016/0009-2509(90)80051-f

Cited by 34 publications

(9 citation statements)

References 14 publications

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“…Van ’t Riet and van der Lans argue that the mixing time for a gas flow number

0.07 < Q_{normalg} / N D^{3} < 0.2

is approximately equal to that under nonaerated conditions. Furthermore, aeration influences the spatial mixing behaviour due to a change in the dominant transport mechanism . The difference in τ circ and flow pattern will affect details in the glucose gradient and residence time distributions in Section but as the difference between τ circ and the reaction timescale (Section ) is large in both cases, the observations are expected to hold at least qualitatively.…”

Section: Methodsmentioning

confidence: 99%

Euler‐Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

Haringa

Tang

Deshmukh

et al. 2016

Engineering in Life Sciences

106

140

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The trajectories, referred to as lifelines, of individual microorganisms in an industrial scale fermentor under substrate limiting conditions were studied using an Euler‐Lagrange computational fluid dynamics approach. The metabolic response to substrate concentration variations along these lifelines provides deep insight in the dynamic environment inside a large‐scale fermentor, from the point of view of the microorganisms themselves. We present a novel methodology to evaluate this metabolic response, based on transitions between metabolic “regimes” that can provide a comprehensive statistical insight in the environmental fluctuations experienced by microorganisms inside an industrial bioreactor. These statistics provide the groundwork for the design of representative scale‐down simulators, mimicking substrate variations experimentally. To focus on the methodology we use an industrial fermentation of Penicillium chrysogenum in a simplified representation, dealing with only glucose gradients, single‐phase hydrodynamics, and assuming no limitation in oxygen supply, but reasonably capturing the relevant timescales. Nevertheless, the methodology provides useful insight in the relation between flow and component fluctuation timescales that are expected to hold in physically more thorough simulations. Microorganisms experience substrate fluctuations at timescales of seconds, in the order of magnitude of the global circulation time. Such rapid fluctuations should be replicated in truly industrially representative scale‐down simulators.

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“…Van ’t Riet and van der Lans argue that the mixing time for a gas flow number

0.07 < Q_{normalg} / N D^{3} < 0.2

Section: Methodsmentioning

confidence: 99%

Euler‐Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

Haringa

Tang

Deshmukh

et al. 2016

Engineering in Life Sciences

106

140

View full text Add to dashboard Cite

show abstract

“…In this case the local mixing is dominating. Support for a bubble-based mixing-scale can be found in Lübbert and Larson (1990). Another physical interpretation of the mixing length is that it is the distance over which a turbulent eddy retains its identity.…”

Section: Mixing Length Conceptmentioning

confidence: 94%

“…Lübbert and Larson (1990) argued that the dominant mixing mechanism arises from bubble wakes. Deckwer et al (1974) and Baird and Rice (1975) developed correlations in which the liquid-phase axial dispersion coefficient E L is correlated to D c .…”

Section: Mixing Length Conceptmentioning

confidence: 99%

New Evidence for the Mixing Length Concept in a Narrow Bubble Column Operated in the Transition Regime

Nedeltchev

Donath

Rabha

et al. 2014

J. Chem. Eng. Japan

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“…[1] Various invasive measurement methods, including pitot tubes, [2] flywheel anemometer, [3] heat-pulse anemometry, [4] hot-film anemometry, [5] and optical probes, [6] have been used to measure such gas-liquid flow field properties as bubble sizes and size distributions, phase holdups, pressure fluctuations and liquid velocity fluctuations. The performance of a bubble column is dictated by the multiphase flow dynamics inside the vessel.…”

Section: Introductionmentioning

confidence: 99%

ECVT imaging of 3D spiral bubble plume structures in gas‐liquid bubble columns

2014

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Electrical Capacitance Volume Tomography (ECVT) is a 3D, real-time imaging technique that is recently developed to image the multiphase flow behaviour in columns of regular or irregular geometries. In this study, the ECVT measurements are conducted to obtain phase holdups and flow structures in bubble columns of a straight-cylinder shape and a tapered-cylinder shape with porous and orifice gas distributors. The phase holdups obtained by the ECVT in a straight-cylinder bubble column with porous gas distributor are verified by other measurement techniques and correlation equations reported in the literature. The flow regimes of the bubble columns are also characterized by the ECVT. Particularly, a dynamic 3D flow structure, which is uniquely represented by the spiral motion of the bubble plumes occurring within the heterogeneous regime of the gas-liquid flow in a straight-cylinder shape bubble column with perforated distributor, is captured for the first time instantaneously over the entire flow field with the ECVT. Other flow behaviour such as the converging flow pattern of the gas bubbles in a tapered-cylinder shape bubble column is also revealed by the ECVT.

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Detailed investigations of the multiphase flow in airlift tower loop reactors

Cited by 34 publications

References 14 publications

Euler‐Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

Euler‐Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

New Evidence for the Mixing Length Concept in a Narrow Bubble Column Operated in the Transition Regime

ECVT imaging of 3D spiral bubble plume structures in gas‐liquid bubble columns

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