Characterization of Bubble Shapes in Non‐Newtonian Fluids by Parametric Equations

Based on experiments with single air bubbles rising in stagnant non‐Newtonian fluids, an innovative model containing the aspect ratio (E) and two parameters (α, β) was proposed and proved to be capable of characterizing the bubble shape from spherical/ellipsoidal to prolate/oblate‐tear with good acc...

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Bibliographic Details
Published inChemical engineering & technology Vol. 42; no. 11; pp. 2321 - 2330
Main Authors Xu, Feishi, Midoux, Noel, Li, Huai-Zhi, Hébrard, Gilles, Dietrich, Nicolas
Format Journal Article
LanguageEnglish
Published Frankfurt Wiley Subscription Services, Inc 01.11.2019
Wiley-VCH Verlag
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Summary:Based on experiments with single air bubbles rising in stagnant non‐Newtonian fluids, an innovative model containing the aspect ratio (E) and two parameters (α, β) was proposed and proved to be capable of characterizing the bubble shape from spherical/ellipsoidal to prolate/oblate‐tear with good accuracy. Several impacts on bubble deformation were investigated, involving the rheological properties of the fluids and different forces exerted on the bubble, which were quantified by multiple dimensionless numbers (e.g., Reynolds, Eötvös, and Deborah number). Within a wide range, the empirical correlations were obtained for parameter β, and between α and β. Together with the shape model, a complete system was set up for bubble shape characterization and prediction that will provide new ideas for future studies on bubble hydrodynamics. Characterization of bubble shapes in non‐Newtonian fluids, from spherical/ellipsoidal to prolate/oblate‐tear, was achieved based both on experiments with single air bubbles rising in stagnant fluids and on a new model containing the aspect ratio and two parameters. The cusp of the bubbles is related to the viscoelasticity and the shear‐thinning level of the solutions.
ISSN:0930-7516
1521-4125
DOI:10.1002/ceat.201800690