Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid
Chemical Engineering Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Micromachines 2021, 12(1), 71; https://doi.org/10.3390/mi12010071
Received: 22 December 2020
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Revised: 8 January 2021
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Accepted: 9 January 2021
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Published: 11 January 2021
(This article belongs to the Special Issue Micro Process-Devices)
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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Keywords:
microfluidics; bubbles; non-Newtonian fluids; CFD
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MDPI and ACS Style
Kontaxi, G.; Stergiou, Y.G.; Mouza, A.A. Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid. Micromachines 2021, 12, 71. https://doi.org/10.3390/mi12010071
AMA Style
Kontaxi G, Stergiou YG, Mouza AA. Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid. Micromachines. 2021; 12(1):71. https://doi.org/10.3390/mi12010071
Chicago/Turabian StyleKontaxi, Georgia, Yorgos G. Stergiou, and Aikaterini A. Mouza. 2021. "Experimental Study of Bubble Formation from a Micro-Tube in Non-Newtonian Fluid" Micromachines 12, no. 1: 71. https://doi.org/10.3390/mi12010071
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