Volumetric mass transfer coefficient in the fermenter agitated by Rushton turbines of various diameters in viscous batch

Petříček, Radim; Moucha, T.; Rejl, F.J.; Valenz, L.; Haidl, Jan

doi:10.1016/j.ijheatmasstransfer.2017.07.112

Cited by 16 publications

(7 citation statements)

References 30 publications

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“…Many industrial process yet involve turbulent gas-liquid mass transfer in complex rheology fluids (e.g., bacteria production in fermentation devices [10,11]), and mass transfer models efficient for Newtonian fluids fail to predict mass transfer efficiency in those situations. Accurate estimation of the mass transfer velocity requires a good knowledge of fundamental and local aspects of turbulence at gas liquid interfaces, which depends itself on the rheology of the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Oscillating grid generating turbulence near gas-liquid interfaces in shear-thinning dilute polymer solutions

et al. 2020

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Understanding the behavior of liquid phase turbulence near gas-liquid interfaces is of great interest in many fundamental, environmental, or industrial applications. For example, near-surface liquid side turbulence is known to enhance the mass transfers between the two phases. Descriptions of this behavior for air-water systems exist in the literature, but the case of turbulence in a shear-thinning liquid phase below a flat gas-liquid interface has never been considered to the best of our knowledge. This paper consists in an experimental characterization of low Reynolds number, oscillating grid generated, nearsurface turbulence in shear-thinning dilute polymer solutions, in the surface-influenced and in the viscous sublayers. The energy transfer mechanism, known in the water case, is evidenced in dilute polymer solutions. A horizontal damping mechanism, similar to the one introduced by surfactants, is evidenced. The evolution of the viscous sublayer depth can be explained by both viscous and shear-thinning effects, and it appears that a critical polymer concentration may exist within the dilute regime.

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Section: Introductionmentioning

confidence: 99%

Oscillating grid generating turbulence near gas-liquid interfaces in shear-thinning dilute polymer solutions

et al. 2020

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“…The study of turbulence, already quite complex in itself, becomes even more challenging when it is done in such fluids. In particular, complex rheology liquids, known as non-Newtonian, are present in many industrial and environmental applications involving turbulent flows, for example in fermentation broths (Gabelle et al 2013;Petříček et al 2017). The complete understanding of complex real life situations requires fundamental description and characterization of turbulence properties in such fluids, and thus adequate experimental or numerical simplified cases of study.…”

Section: Introductionmentioning

confidence: 99%

Flow around an oscillating grid in water and shear-thinning polymer solution at low Reynolds number

et al. 2019

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The study of turbulence in complex fluids is of great interest in many environmental and industrial applications, in which the interactions between liquid phase rheology, turbulence, and other phenomena such as mixing or heat and mass transfer have to be understood. Oscillating grid stirred tanks have been used for many purposes in research involving turbulence. However, the mechanisms of turbulence production by the oscillating grid itself have never been studied, and oscillating grid turbulence (OGT) remained undescribed in non-Newtonian, shear-thinning, dilute polymer solutions until recently (Lacassagne et al., in Phys Fluids 31(8):083,102, 2019). The aim of this paper is to study the influence of the shear-thinning property of dilute polymer solutions (DPS), such as xanthan gum (XG), on mean flow, oscillatory flows, and turbulence around an oscillating grid. Liquid phase velocity is measured by particle image velocimetry (PIV) in a vertical plane above the central grid bar. Mean, oscillatory and turbulent components of the velocity fields are deduced by triple Hussain-Reynolds decomposition based on grid phase-resolved measurements. Outside of the grid swept region, the amplitude of oscillatory fluctuations quickly become negligible compared to that of turbulent fluctuations, and the triple and classical Reynolds decomposition become equivalent. Oscillatory jets and wakes behind the grid and their interactions are visualized. Turbulent (Reynolds) and oscillatory stresses are used to evidence a modification of oscillatory flow and turbulence intensity repartition in and around the grid swept region. Energy transfer terms between mean, oscillatory and turbulent flows are estimated and used to describe turbulence production in the grid swept region. Energy is injected by the grid into the oscillatory component. In water, it is transferred to turbulence mostly inside the grid swept region. In DPS, oscillatory flow persists outside of the grid swept zone. Energy is transferred not only to turbulence , in the grid swept region, and far from the tank's walls, but also to the mean flow, leading to an enhancement of the latter. Mean flow production and enhancement mechanisms are explainable by oscillatory jet variable symmetry and intensity, and by time-and space-variable viscosity. Backward transfer from turbulence to oscillatory flow is also evidenced in DPS. Finally, using phased root mean square (rms) values of turbulent velocity fluctuations, it is shown that in water, the decay of turbulence intensity behind an oscillating grid can be related to the decay of fixed grid turbulence for specific grid positions, a result no longer valid in DPS.

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“…In this work, turbulent dissolution and mass transfer of carbon dioxide into water and a moderately shear-thinning liquid phase was studied experimentally coupling SPIV and I Local measurement of turbulent mass fluxes such as those reported here are highly desirable in the context of mass transfer modelling, for which first order gradient model appear insufficient. Extensive effort has been and is still being made to relate mass transfer velocity k L to local turbulence properties [20,48] and our experimental contribution can be used to power this modelling effort, that is now facing the challenge of complex fluid rheology encountered in many industrial applications [49]. Three-component information brought by SPIV, or other more elaborate three-dimensional methods such as PTV [38] applied near-surface, could be useful in the context of surface divergence modelling [50,48].…”

Section: Discussionmentioning

confidence: 99%

Turbulent mass transfer near gas-liquid interfaces in water and shear-thinning dilute polymer solution

Lacassagne

Hajem

Champagne

et al. 2022

International Journal of Heat and Mass Transfer

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Volumetric mass transfer coefficient in the fermenter agitated by Rushton turbines of various diameters in viscous batch

Cited by 16 publications

References 30 publications

Oscillating grid generating turbulence near gas-liquid interfaces in shear-thinning dilute polymer solutions

Oscillating grid generating turbulence near gas-liquid interfaces in shear-thinning dilute polymer solutions

Flow around an oscillating grid in water and shear-thinning polymer solution at low Reynolds number

Turbulent mass transfer near gas-liquid interfaces in water and shear-thinning dilute polymer solution

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