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

Nalajala, Venkata Swamy; Kishore, Nanda

doi:10.1016/j.minpro.2015.04.022

Cited by 7 publications

(12 citation statements)

References 37 publications

(36 reference statements)

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“…The literatures on the motion of and mass/heat transfer from clean, partially contaminated and fully contaminated bubbles to Newtonian liquids are thoroughly reviewed elsewhere ; however, the literature on analogous problems in non‐Newtonian liquids are presented herein.…”

Section: Literature Reviewmentioning

confidence: 99%

“…The segregated approach is used to obtain the velocity and temperature profiles. In other words, first the momentum equations are solved to obtain the steady velocity profile (as described elsewhere ), and by using the obtained velocity profile, the energy equation is solved for temperature profile. Further, the flow is assumed to be steady and axisymmetric.…”

Section: Problem Statement and Mathematical Descriptionmentioning

confidence: 99%

“…The stagnant cap model has been extensively adopted to interpret experimental results and found that this model is consistent with experimental results not only at low to moderate Reynolds numbers but also at large values of the Reynolds numbers. Furthermore, this model is also tested theoretically by many researchers and proved to be reliable under a wide range of Reynolds numbers . As per this model, contaminants can adsorb at the first front half of the bubble surface and move towards the backside of the bubble because of the surface advection caused by the main flow .…”

Section: Introductionmentioning

confidence: 98%

“…Therefore, both from theoretical and industrial applications viewpoints, development of results on the motion and heat transfer from the contaminated confined bubbles to surrounding contaminated non‐Newtonian liquids is a prerequisite for the rational design and operation of liquid–gas contacting equipment. In this connection, recently Kishore and coworkers reported numerical results on a series of analogous problems. For instance, Kishore and colleagues delineated the flow and drag behavior of contaminated bubbles in Newtonian and shear‐thinning power‐law fluids in the range of conditions: Re = 10 to 200, n = 0.6 to 1 and α = 0 to 180˚ using their in‐house CFD solver namely semi‐implicit marker and cell algorithm implemented on a staggered grid arrangement in spherical coordinates.…”

Section: Introductionmentioning

confidence: 99%

“…The corresponding heat transfer characteristics of single unconfined contaminated bubbles in power‐law fluids is numerically investigated by Nalajala and Kishore for a range of conditions Re = 0.1 to 200; n = 0.2 to 1.6, Pr = 1 to 1000 and α = 0 to 180˚ using ANSYS Fluent. In a recent work, Nalajala and Kishore presented numerical results on the motion of confined contaminated bubbles in surrounding power‐law liquids over a wider range of Reynolds number, power‐law index, stagnant cap angle and confinement ratio. The corresponding numerical results associated with the heat transfer characteristics of confined contaminated bubbles in power‐law liquids are presented herein.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer from Confined Contaminated Bubbles to Power‐Law Liquids at Low to Moderate Reynolds and Prandtl Numbers

Kishore

Nalajala

2016

Heat Trans. Asian Res.

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In this work combined effects of the wall confinement and the power-law fluid viscosity on the heat transfer phenomena of contaminated bubbles are reported through numerical investigations. In order to delineate the effect of insoluble surfactants the spherical stagnant cap model is adopted. The solver is thoroughly validated by comparing the present results with their literature counterparts. Further, extensive new results are reported on the isotherm contours and average Nusselt numbers of confined contaminated bubbles in the range of conditions: Reynolds number, Re: 0.1 to 200; Prandtl number, Pr: 1 to 1000; power-law index, n: 0.2 to 1.6 and stagnant cap angle, : 0 to 180°. Briefly, results are indicative of the following observations. The temperature contours are increasingly sucked towards the rear end of the bubble with the increase in Reynolds number and/or with the increase in Prandtl number and/or with the decrease in power-law index and/or with the decrease in stagnant cap angle. At Re ≤ 1 and Pr ≤ 10, the average Nusselt number is almost independent of power-law indices and the stagnant cap angle. For Pe > 10, regardless of values of the confinement ratio and Reynolds number, for ≥ 60 the average Nusselt number decreases with an increasing stagnant cap angle whereas for < 60 the effect of contamination is found to be insignificant. The increase in the average Nusselt number with an increasing confinement ratio would occur only at moderate to large values of Reynolds and Prandtl numbers regardless of the values of the power-law index provided that ≥ 60°. C⃝ 2016 Wiley Periodicals, Inc. Heat Trans Asian Res, 46 (7): 681-702, 2017; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj).

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Section: Literature Reviewmentioning

confidence: 99%

Section: Problem Statement and Mathematical Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heat Transfer from Confined Contaminated Bubbles to Power‐Law Liquids at Low to Moderate Reynolds and Prandtl Numbers

Kishore

Nalajala

2016

Heat Trans. Asian Res.

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Droplet Shape and Drag Coefficients in Non‐Newtonian Fluids: A Review

Sun

2023

ChemBioEng Reviews

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The motion of droplets in non‐Newtonian fluids is widely present in ubiquitous industrial processes. Understanding the droplet motion characteristics is important for optimizing the design of related processes. Here the progress in the research on the droplet motion characteristics in non‐Newtonian fluids is reviewed. The mechanism of droplet deformation in non‐Newtonian fluids were elucidated, the influence of different rheological properties on droplet shape was discussed, and the empirical correlations of droplet aspect ratio were summarized. Moreover, the dimensionless correlations of drag coefficient were discussed. There are relatively few drag coefficient correlations of droplets in non‐Newtonian fluids, while the correlation of drag coefficients of bubbles in non‐Newtonian fluids can provide some reference. Finally, the possible prospects for future studies of the subject were proposed.

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CFD study on rise and deformation characteristics of buoyancy-driven spheroid bubbles in stagnant Carreau model non-Newtonian fluids

Gollakota

Kishore

2017

Theor. Comput. Fluid Dyn.

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

Cited by 7 publications

References 37 publications

Heat Transfer from Confined Contaminated Bubbles to Power‐Law Liquids at Low to Moderate Reynolds and Prandtl Numbers

Heat Transfer from Confined Contaminated Bubbles to Power‐Law Liquids at Low to Moderate Reynolds and Prandtl Numbers

Droplet Shape and Drag Coefficients in Non‐Newtonian Fluids: A Review

CFD study on rise and deformation characteristics of buoyancy-driven spheroid bubbles in stagnant Carreau model non-Newtonian fluids

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