Effect of contamination on rise velocity of bubble swarms at moderate Reynolds numbers

Nalajala, Venkata Swamy; Kishore, Nanda; Chhabra, R.P.

doi:10.1016/j.cherd.2013.10.006

Cited by 14 publications

(8 citation statements)

References 33 publications

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“…One focus is on the changing mass transfer when surfactants are added [10,17]. In recent years, the effect of surfactants has also been studied numerically [18,19]. Since the present work is focusing on electrolytes, specifically NaCl, added to water, a particular application is also the emergency cooling of nuclear power reactors with seawater as was done in the Daiichi accident near Fukushima in 2011 after an earthquake (e.g., [20]).…”

Section: Introductionmentioning

confidence: 99%

The Bubble Shape in Contaminated Bubbly Flows: Results for Different NaCl Concentrations in Purified Water

et al. 2018

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Abstract:The bubble shape influences the transfer of momentum and heat/mass between the bubble and the surrounding fluid as well as the flow field around the bubble. The shape is determined by the interaction of the fluid field in the bubble, the physics on the surface, and the surrounding flow field. It is well known that contaminations can disturb the surface physics so that the bubble shape can be influenced. Indeed, an influence of sodium chloride (NaCl) on the hydrodynamics of bubbly flows was shown for air/water systems in previous studies. The aim of the present work is to investigate if, and to what extent, the NaCl concentration affects the bubble shape in bubble columns. For this purpose, several experiments at the Helmholtz-Zentrum Dresden-Rossendorf and at the pilot-scale bubble column at the Politecnico di Milano are evaluated. The experiments were executed independently from each other and were evaluated with different methods. All experiments show that the bubble shape is not distinctly affected in the examined concentration range from 0 to 1 M NaCl, which is in contrast to a previous study on single bubbles. Therefore, the effect of NaCl on the hydrodynamics of bubbly flows is not induced by the bubble shape.

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Section: Introductionmentioning

confidence: 99%

The Bubble Shape in Contaminated Bubbly Flows: Results for Different NaCl Concentrations in Purified Water

et al. 2018

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“…9–11 are solved numerically using a finite difference method‐based simplified marker and cell semi‐implicit algorithm. The detailed solution methodology is presented elsewhere 46–49 and hence only salient features are presented herein. The algorithm employed here is a simplified version of the explicit algorithm from Harlow and Welch 50, and is implemented in spherical coordinates on a staggered grid arrangement.…”

Section: Numerical Methodologymentioning

confidence: 99%

Slip in Flow through Assemblages of Spherical Particles at Low to Moderate Reynolds Numbers

Kishore

Ramteke

2016

Chem Eng & Technol

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Effects of slip velocity and volume fraction of slip spheres on the momentum transfer characteristics of assemblages of slip spheres are numerically investigated. The fluid slip along the surface of the sphere is considered by Navier's linear slip model. The dimensionless governing continuity and momentum equations are solved using a semi-implicit marker and cell method implemented on a staggered grid arrangement in spherical coordinates. The convection and viscous terms of momentum equations are discretized by means of the QUICK scheme and a second-order central differencing scheme, respectively. The present numerical solver is benchmarked via grid independence and comparisons with the existing literature values. Results were obtained over a wide range of pertinent dimensionless numbers such as the Reynolds number, volume fraction of the dispersed phase, and dimensionless slip parameter.

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“…In general, not only the contamination (surfactants) affect the motion of the bubbles but also the presence of surrounding bubbles (swarms of bubbles), wall retardation due to the presence of confining container wall and rheology of the surrounding continuous liquid will also affect the overall momentum transfer characteristics of the bubble motion. Thus in our previous works, effects of the surrounding bubbles on the overall momentum transfer characteristics of partially contaminated bubble swarms (Nalajala et al, 2014) and effects of power-law type nonNewtonian rheology of surrounding continuous fluids on the flow and drag behavior of partially contaminated unconfined bubbles Kishore, 2014a, 2014b) are presented. Therefore, in this work, additional effects of confining wall retardation on the overall momentum transfer characteristics of partially contaminated confined bubbles in surfactant-laden power-law type non-Newtonian fluids are delineated.…”

Section: Introductionmentioning

confidence: 98%

Motion of partially contaminated bubbles in power-law liquids: Effect of wall retardation

Nalajala

Kishore

2015

International Journal of Mineral Processing

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Effect of contamination on rise velocity of bubble swarms at moderate Reynolds numbers

Cited by 14 publications

References 33 publications

The Bubble Shape in Contaminated Bubbly Flows: Results for Different NaCl Concentrations in Purified Water

The Bubble Shape in Contaminated Bubbly Flows: Results for Different NaCl Concentrations in Purified Water

Slip in Flow through Assemblages of Spherical Particles at Low to Moderate Reynolds Numbers

Motion of partially contaminated bubbles in power-law liquids: Effect of wall retardation

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