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Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid

Over the last few years, microbubbles have found application in biomedicine. In this study, the characteristics of bubbles formed when air is introduced from a micro-tube (internal diameter 110 μm) in non-Newtonian shear thinning fluids are studied. The dependence of the release time and the size of...

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Detalles Bibliográficos
Autores principales: Kontaxi, Georgia, Stergiou, Yorgos G., Mouza, Aikaterini A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827566/
https://www.ncbi.nlm.nih.gov/pubmed/33440872
http://dx.doi.org/10.3390/mi12010071
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author Kontaxi, Georgia
Stergiou, Yorgos G.
Mouza, Aikaterini A.
author_facet Kontaxi, Georgia
Stergiou, Yorgos G.
Mouza, Aikaterini A.
author_sort Kontaxi, Georgia
collection PubMed
description Over the last few years, microbubbles have found application in biomedicine. In this study, the characteristics of bubbles formed when air is introduced from a micro-tube (internal diameter 110 μm) in non-Newtonian shear thinning fluids are studied. The dependence of the release time and the size of the bubbles on the gas phase rate and liquid phase properties is investigated. The geometrical characteristics of the bubbles are also compared with those formed in Newtonian fluids with similar physical properties. It was found that the final diameter of the bubbles increases by increasing the gas flow rate and the liquid phase viscosity. It was observed that the bubbles formed in a non-Newtonian fluid have practically the same characteristics as those formed in a Newtonian fluid, whose viscosity equals the asymptotic viscosity of the non-Newtonian fluid, leading to the assumption that the shear rate around an under-formation bubble is high, and the viscosity tends to its asymptotic value. To verify this notion, bubble formation was simulated using Computational Fluid Dynamics (CFD). The simulation results revealed that around an under-formation bubble, the shear rate attains a value high enough to lead the viscosity of the non-Newtonian fluid to its asymptotic value.
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spelling pubmed-78275662021-01-25 Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid Kontaxi, Georgia Stergiou, Yorgos G. Mouza, Aikaterini A. Micromachines (Basel) Article Over the last few years, microbubbles have found application in biomedicine. In this study, the characteristics of bubbles formed when air is introduced from a micro-tube (internal diameter 110 μm) in non-Newtonian shear thinning fluids are studied. The dependence of the release time and the size of the bubbles on the gas phase rate and liquid phase properties is investigated. The geometrical characteristics of the bubbles are also compared with those formed in Newtonian fluids with similar physical properties. It was found that the final diameter of the bubbles increases by increasing the gas flow rate and the liquid phase viscosity. It was observed that the bubbles formed in a non-Newtonian fluid have practically the same characteristics as those formed in a Newtonian fluid, whose viscosity equals the asymptotic viscosity of the non-Newtonian fluid, leading to the assumption that the shear rate around an under-formation bubble is high, and the viscosity tends to its asymptotic value. To verify this notion, bubble formation was simulated using Computational Fluid Dynamics (CFD). The simulation results revealed that around an under-formation bubble, the shear rate attains a value high enough to lead the viscosity of the non-Newtonian fluid to its asymptotic value. MDPI 2021-01-11 /pmc/articles/PMC7827566/ /pubmed/33440872 http://dx.doi.org/10.3390/mi12010071 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kontaxi, Georgia
Stergiou, Yorgos G.
Mouza, Aikaterini A.
Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title_full Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title_fullStr Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title_full_unstemmed Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title_short Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
title_sort experimental study of bubble formation from a micro-tube in non-newtonian fluid
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827566/
https://www.ncbi.nlm.nih.gov/pubmed/33440872
http://dx.doi.org/10.3390/mi12010071
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