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Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions

In this study, acoustic streaming flows inside micro-channels induced by three different types of obstruction—gaseous bubble, liquid droplet and solid bulge—are compared and investigated experimentally by particle tracking velocimetry (PTV) and numerically using the finite element method (FEM). The...

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Autores principales: Lu, Hsin-Fu, Tien, Wei-Hsin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601848/
https://www.ncbi.nlm.nih.gov/pubmed/32993101
http://dx.doi.org/10.3390/mi11100891
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author Lu, Hsin-Fu
Tien, Wei-Hsin
author_facet Lu, Hsin-Fu
Tien, Wei-Hsin
author_sort Lu, Hsin-Fu
collection PubMed
description In this study, acoustic streaming flows inside micro-channels induced by three different types of obstruction—gaseous bubble, liquid droplet and solid bulge—are compared and investigated experimentally by particle tracking velocimetry (PTV) and numerically using the finite element method (FEM). The micro-channels are made by poly(dimethylsiloxane) (PDMS) using soft lithography with low-cost micro-machined mold. The characteristic dimensions of the media are 0.2 mm in diameter, and the oscillation generated by piezoelectric actuators has frequency of 12 kHz and input voltages of 40 V. The experimental results show that in all three obstruction types, a pair of counter-rotating vortical patterns were observed around the semi-circular obstructions. The gaseous bubble creates the strongest vortical streaming flow, which can reach a maximum of 21 mm/s, and the largest u component happens at Y/D = 0. The solid case is the weakest of the three, which can only reach 2 mm/s. The liquid droplet has the largest v components and speed at Y/D = 0.5 and Y/D = 0.6. Because of the higher density and incompressibility of liquid droplet compared to the gaseous bubble, the liquid droplet obstruction transfers the oscillation of the piezo plate most efficiently, and the induced streaming flow region and average speed are both the largest of the three. An investigation using numerical simulation shows that the differing interfacial conditions between the varying types of obstruction boundaries to the fluid may be the key factor to these differences. These results suggest that it might be more energy-efficient to design an acoustofluidic device using a liquid droplet obstruction to induce the stronger streaming flow.
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spelling pubmed-76018482020-11-01 Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions Lu, Hsin-Fu Tien, Wei-Hsin Micromachines (Basel) Article In this study, acoustic streaming flows inside micro-channels induced by three different types of obstruction—gaseous bubble, liquid droplet and solid bulge—are compared and investigated experimentally by particle tracking velocimetry (PTV) and numerically using the finite element method (FEM). The micro-channels are made by poly(dimethylsiloxane) (PDMS) using soft lithography with low-cost micro-machined mold. The characteristic dimensions of the media are 0.2 mm in diameter, and the oscillation generated by piezoelectric actuators has frequency of 12 kHz and input voltages of 40 V. The experimental results show that in all three obstruction types, a pair of counter-rotating vortical patterns were observed around the semi-circular obstructions. The gaseous bubble creates the strongest vortical streaming flow, which can reach a maximum of 21 mm/s, and the largest u component happens at Y/D = 0. The solid case is the weakest of the three, which can only reach 2 mm/s. The liquid droplet has the largest v components and speed at Y/D = 0.5 and Y/D = 0.6. Because of the higher density and incompressibility of liquid droplet compared to the gaseous bubble, the liquid droplet obstruction transfers the oscillation of the piezo plate most efficiently, and the induced streaming flow region and average speed are both the largest of the three. An investigation using numerical simulation shows that the differing interfacial conditions between the varying types of obstruction boundaries to the fluid may be the key factor to these differences. These results suggest that it might be more energy-efficient to design an acoustofluidic device using a liquid droplet obstruction to induce the stronger streaming flow. MDPI 2020-09-26 /pmc/articles/PMC7601848/ /pubmed/32993101 http://dx.doi.org/10.3390/mi11100891 Text en © 2020 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
Lu, Hsin-Fu
Tien, Wei-Hsin
Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title_full Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title_fullStr Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title_full_unstemmed Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title_short Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions
title_sort comparison of acoustic streaming flow patterns induced by solid, liquid and gas obstructions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601848/
https://www.ncbi.nlm.nih.gov/pubmed/32993101
http://dx.doi.org/10.3390/mi11100891
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