Drag Coefficients of Single Bubbles under Normal and Micro Gravity Conditions.

Tomiyama, Akio; Kataoka, Isao; Žun, Iztok; Sakaguchi, Tadashi

doi:10.1299/jsmeb.41.472

Cited by 555 publications

(311 citation statements)

References 3 publications

Supporting

Mentioning

261

Contrasting

Unclassified

Order By: Relevance

“…The drag, lift, wall lubrication and turbulent dispersion forces were taken into account for gas and liquid momentum transfer. The drag coefficient model from Tomiyama et al [22] was used to calculate drag force for each bubble size group. The Tomiyama drag coefficient model, being developed based on the balance of forces acting on a bubble and available theoretical and empirical correlations of terminal rising velocity, is well suited for gas-liquid flows where the bubbles can be of different size to a certain extent.…”

Section: Coupled Cfd-pbm Modelmentioning

confidence: 99%

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Han

Sha

Лаари

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

-Hydrodynamics of an AirLift Reactor (ALR) with tap water and non-Newtonian fluid was studied experimentally and by numerical simulations. The Population Balance Model (PBM) with multiple breakup and coalescence mechanisms was used to describe bubble size characteristics in the ALR. The interphase forces for closing the two-fluid model were formulated by considering the effect of Bubble Size Distribution (BSD). The BSD in the ALR obtained from the coupled Computational Fluid Dynamics (CFD)-PBM model was validated against results from digital imaging measurements. The simulated velocity fields of both the gas and liquid phases were compared to measured fields obtained with Particle Image Velocimetry (PIV). The simulated results show different velocity field profile features at the top of the ALR between tap water and nonNewtonian fluid, which are in agreement with experiments. In addition, good agreement between simulations and experiments was obtained in terms of overall gas holdup and bubble Sauter mean diameter. NOMENCLATURE SymbolsVolume fraction of gas/liquid phase, 1 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

show abstract

Section: Coupled Cfd-pbm Modelmentioning

confidence: 99%

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Han

Sha

Лаари

et al. 2017

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

show abstract

“…are the drag coefficient and the frontal bubble area. We calculate the drag coefficient with the expression of Tomiyama [21] for contaminated systems; all other parameters are known. The calculated bubble velocities as a function for different particle velocities are shown in Fig.…”

Section: -2mentioning

confidence: 99%

Dynamics of Single Rising Bubbles in Neutrally Buoyant Liquid-Solid Suspensions

et al. 2013

View full text Add to dashboard Cite

We experimentally investigate the effect of particles on the dynamics of a gas bubble rising in a liquidsolid suspension while the particles are equally sized and neutrally buoyant. Using the Stokes number as a universal scale, we show that when a bubble rises through a suspension characterized by a low Stokes number (in our case, small particles), it will hardly collide with the particles and will experience the suspension as a pseudoclear liquid. On the other hand, when the Stokes number is high (large particles), the high particle inertia leads to direct collisions with the bubble. In that case, Newton's collision rule applies, and direct exchange of momentum and energy between the bubble and the particles occurs. We present a simple theory that describes the underlying mechanism determining the terminal bubble velocity.

show abstract

“…In the distorted regime, the drag coefficient is dependent on the particle shape, which can be expressed through the Eötvös number. Correlations that take into account the bubble shape have been given by Ishii and Zuber (1979) and by Tomiyama et al (1998). These correlations are valid for contaminated systems, where bubbles behave as objects with immobile surfaces, see the following equations: The main drawback of all the previously mentioned drag coefficient correlations is that they are valid only in stagnant fluids.…”

Section: Flow Equationsmentioning

confidence: 99%

“…These bubbles can be considered to be perfectly spherical. Thus, modified models that take into account significant deformations of larger bubbles and a decrease of drag in dense dispersions (Ishii and Zuber, 1979;Tomiyama et al, 1998) or interactions of bubbles with turbulent eddies (Bakker and van den Akker, 1994;Brucato et al, 1998;Montante et al, 2007) have been derived.…”

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

View full text Add to dashboard Cite

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.

show abstract

Drag Coefficients of Single Bubbles under Normal and Micro Gravity Conditions.

Cited by 555 publications

References 3 publications

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Dynamics of Single Rising Bubbles in Neutrally Buoyant Liquid-Solid Suspensions

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

Contact Info

Product

Resources

About