Hydrodynamic Behavior of a Single Bubble Rising in Viscous Liquids

Cai, Ziqi; Bao, Yuyun; Gao, Zhengming

doi:10.1016/s1004-9541(09)60149-x

Cited by 33 publications

(19 citation statements)

References 11 publications

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“…1-3 Nowadays, the bubble column reactors are widely used as gas-liquid interface equipments in various industrial sectors such as chemical, petrochemical, pharmaceutical, etc., involving reactions such as oxidation, chlorination, alkylation, polymerization and hydrogenation, and eventually they are employed as bioreactors to produce valuable products like enzymes, proteins, antibiotics, etc. 1, 2 Recently, a number of experimental and theoretical studies 4 peculiar properties, for instance, shear-thinning, viscoelasticity, rod-climbing and tubeless siphon. [11][12][13] Hence, the bubble rising behavior and interaction in non-Newtonian fluids are more complex and also the relevant researches are quite rare.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] Nowadays, bubble column reactors are widely used as gas-liquid interface equipment in various industrial sectors such as chemical, petrochemical, pharmaceutical etc., in reactions such as oxidation, chlorination, alkylation, polymerization and hydrogenation, and are employed as bioreactors to produce valuable products like enzymes, proteins, antibiotics, etc. 1,2 Recently, a number of experimental and theoretical studies [4][5][6][7][8][9][10] have been carried out on the formation and rise characteristics of single bubbles in stagnant uids under the buoyancy force in Newtonian uids. The literature provides almost complete information regarding single bubble formation and rise characteristics.…”

Section: Introductionmentioning

confidence: 99%

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A pair of bubbles’ rising dynamics in a xanthan gum solution: a CFD study

2015

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The motion and interaction of a bubble pair in a non-Newtonian fluid (xanthan gum solution) were numerically simulated using volume of fluid (VOF) method, in which the continuous surface tension model and the power-law model were adopted to represent surface tension and rheological properties of non-Newtonian fluids, respectively. The effects of initial horizontal bubble interval, oblique alignment and rheological properties of non-Newtonian fluids on a pair of bubbles rising side-by-side were evaluated in this study. The results indicated that for the case with non-dimensional initial horizontal interval of bubble h* = 4.0, the interaction between the bubbles shows a minimum repulsive effect. Moreover, for the oblique angle alignment a greater repulsive force between the bubbles was seen when the angle was reduced.However, oblique coalescence occurred due to the higher attraction between the bubbles at higher angle, which is independent of flow index It is also found that the repulsion effect as well as the variation of the bubble shape from spherical to wobbling are more significant at a lower flow index (n < 0.5) due to the shear-thinning effect as well as the differences of their flow field structures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A pair of bubbles’ rising dynamics in a xanthan gum solution: a CFD study

2015

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“…On the other hand, electro‐flotation is a dynamic process influenced by many factors such as resistance impact, in addition to the velocity and shape of bubbles. For the calculation of the terminal velocity of bubbles, we use the following equation proposed by Cai et al, which reveals the relationship between the velocity and terminal velocity of bubbles with the flow velocity on the basis of the following equation:

U_{T} = \frac{U_{T}^{W} U_{b}}{\sqrt{{((), U_{normalb})}^{2} + {((), U_{normalT}^{normalW})}^{2}}},

where U b represents the velocity of bubbles,

U_{b} = \frac{1}{18} \frac{ρ_{L} - ρ_{G}}{μ_{normalL}} {gD}_{e}^{2}

;

U_{T}^{W}

represents the velocity of fluid surrounding bubbles,

U_{T}^{W} = \sqrt{\frac{2 σ}{D_{normale} (ρ_{normalL} + ρ_{normalG})}} + \frac{{italicgD}_{normale}}{2}

; D e represents the equivalent diameter of bubbles; μ L represents the liquid viscosity; ρ L and ρ G represent the liquid and gas densities, respectively; and σ represents the surface tension of the liquid.…”

Section: Resultsmentioning

confidence: 99%

Effects of bubble size, velocity, and particle agglomeration on the electro‐flotation kinetics of fine cassiterite

Ren

Zeng

Nguyen

et al. 2019

Asia-Pacific J Chem Eng

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Hydrodynamic behavior of fine particles and bubbles and their influences on the particle-bubble collision efficiency (E c ) in an electro-flotation system were analyzed in this study. The influence of sodium oleate on the agglomeration of cassiterite particles and the effect of electrolyte (Na 2 SO 4 ) concentration on the zeta potential of cassiterite were investigated in detail, respectively. Bubble trajectory was recorded by using a high-speed camera to investigate the dynamic process in terms of bubble velocity. Moreover, bubble size was taken into account in the determination of the relationship between bubble velocity and E c . The Reynolds number (Re b ) was calculated to be 4.77 for hydrogen (H 2 ) bubbles with a mean diameter of 52 μm. The highest recovery of cassiterite particles (<10 μm) was obtained by using 20 μm bubbles during flotation. The results indicate that the Yoon-Luttrell intermediate fluid (between the Stokes and potential flows) condition is applicable for the cassiterite electro-flotation system, and E c is improved by controlling the size and velocity of the hydrogen bubble, and the agglomeration of fine cassiterite particles in electro-flotation.Additionally, it was greatly inspired to explore bubble-particle attachment in dissolved air flotation from these results.

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“…It is 459 estimated in Tomiyama et al (2002) using the empirical corre-460 lation for the aspect ratio of Wellek et al (1966). In the litera-461 ture, recent studies (Cai et al, 2010;Legendre et al, 2012) and 462 dierent correlations (Yamoah et al, 2015;Besagni and Inzoli, 463 2016) related with the aspect ratio of bubbles can be found. The 464 latter two correlations and the Wellek's one give positive values 465 for the lift coecients for the BSD of this work.…”

Section: Interfacial Forces Coecientsmentioning

confidence: 99%

A CFD-DEM solver to model bubbly flow. Part I: Model development and assessment in upward vertical pipes

Peña-Monferrer

Monrós-Andreu

Chiva

et al. 2018

Chemical Engineering Science

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In the computational modeling of two-phase flow, many uncertainties are usually faced in simulations and validations with experiments. This has traditionally made it dicult to provide a general method to predict the two-phase flow characteristics for any geometry and condition, even for bubbly flow regimes. Thus, we focus our research on studying in depth the bubbly flow modeling and validation from a critical point of view. The conditions are intentionally limited to scenarios where coalescence and breakup can be neglected, to concentrate on the study of bubble dynamics and its interaction with the main fluid. This study required the development of a solver for bubbly flow with higher resolution level than TFM and a new methodology to obtain the data from the simulation. Part I shows the development of a solver based on the CFD-DEM formulation. The motion of each bubble is computed individually with this solver and aspects as inhomogeneity, nonlinearity of the interfacial forces, bubble-wall interactions and turbulence eects in interfacial forces are taken into account. To develop the solver, several features that are not usually required for traditional CFD-DEM simulations but are relevant for bubbly flow in pipes have been included. Models for the assignment of void fraction into the grid, seeding of bubbles at the inlet, pressure change influence on the bubble size and turbulence eects on both phases have been assessed and compared with experiments for an upward vertical pipe scenario. Finally, the bubble path for bubbles of dierent size have been investigated and the interfacial forces analyzed.

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Hydrodynamic Behavior of a Single Bubble Rising in Viscous Liquids

Cited by 33 publications

References 11 publications

A pair of bubbles’ rising dynamics in a xanthan gum solution: a CFD study

A pair of bubbles’ rising dynamics in a xanthan gum solution: a CFD study

Effects of bubble size, velocity, and particle agglomeration on the electro‐flotation kinetics of fine cassiterite

A CFD-DEM solver to model bubbly flow. Part I: Model development and assessment in upward vertical pipes

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