Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations

This study presents experiments and computational simulations of single-layer passive micromixer designs. The proposed designs consist of chains of interlocking semicircles and omega-shaped mixing modules. The performance of the new designs is compared with the concentric spiral channel configuratio...

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Main Authors: Ala’aldeen Al-Halhouli, Aiman Alshare, Mukeet Mohsen, Maher Matar, Andreas Dietzel, Stephanus Büttgenbach
Format: Article
Language:English
Published: MDPI AG 2015-07-01
Series:Micromachines
Subjects:
Online Access:http://www.mdpi.com/2072-666X/6/7/953
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author Ala’aldeen Al-Halhouli
Aiman Alshare
Mukeet Mohsen
Maher Matar
Andreas Dietzel
Stephanus Büttgenbach
author_facet Ala’aldeen Al-Halhouli
Aiman Alshare
Mukeet Mohsen
Maher Matar
Andreas Dietzel
Stephanus Büttgenbach
author_sort Ala’aldeen Al-Halhouli
collection DOAJ
description This study presents experiments and computational simulations of single-layer passive micromixer designs. The proposed designs consist of chains of interlocking semicircles and omega-shaped mixing modules. The performance of the new designs is compared with the concentric spiral channel configuration. The micromixers are intended to be integrated into a lab on chip (LOC) micro-system that operates under continuous flow conditions. The purpose behind the multi-curvature in these designs is the introduction of Dean vortices in addition to molecular diffusion in order to enhance the mixing performance. The micromixers were fabricated in PDMS (Polydimethylsiloxane) and bonded to a glass substrate. A three-dimensional computational model of micromixers was carried out using Fluent ANSYS. In experiments, the mixing of a 1 g/L fluorescein isothiocyanate diluted in distilled water was observed and photographed using a charge-coupled device (CCD) microscopic camera. The obtained images were processed to determine the mixing intensity at different Reynolds numbers. The standard deviation (σ) of the fluorescence indicates the mixing completeness, which was calculated along the width of the channel at various locations downstream from the channel inlet. The value of σ = 0.5 indicates unmixed streams and 0 is for complete mixing. It is found that the two new designs have a standard deviation of nearly 0.05. Additionally, complete mixing was observed at the channel outlet as demonstrated by the fluorescence images and the numerical results. However, the location of complete mixing at different positions depends on the Reynolds number, which varies between 0.01 and 50. Good agreement was found between the experiment and the numerical results. A correlation to predict the length scale where complete mixing can be achieved is given in terms of the radius of curvature, the mixing module, and the Reynolds number.
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spelling doaj.art-f6c57e46f36c452f98ac845bb46501402022-12-22T02:07:48ZengMDPI AGMicromachines2072-666X2015-07-016795396810.3390/mi6070953mi6070953Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and SimulationsAla’aldeen Al-Halhouli0Aiman Alshare1Mukeet Mohsen2Maher Matar3Andreas Dietzel4Stephanus Büttgenbach5Institute of Microtechnology, Technical University of Braunschweig, Braunschweig 38106, GermanyMechanical Engineering Department, German Jordanian University, Amman 11180, JordanInstitute of Microtechnology, Technical University of Braunschweig, Braunschweig 38106, GermanyInstitute of Microtechnology, Technical University of Braunschweig, Braunschweig 38106, GermanyInstitute of Microtechnology, Technical University of Braunschweig, Braunschweig 38106, GermanyInstitute of Microtechnology, Technical University of Braunschweig, Braunschweig 38106, GermanyThis study presents experiments and computational simulations of single-layer passive micromixer designs. The proposed designs consist of chains of interlocking semicircles and omega-shaped mixing modules. The performance of the new designs is compared with the concentric spiral channel configuration. The micromixers are intended to be integrated into a lab on chip (LOC) micro-system that operates under continuous flow conditions. The purpose behind the multi-curvature in these designs is the introduction of Dean vortices in addition to molecular diffusion in order to enhance the mixing performance. The micromixers were fabricated in PDMS (Polydimethylsiloxane) and bonded to a glass substrate. A three-dimensional computational model of micromixers was carried out using Fluent ANSYS. In experiments, the mixing of a 1 g/L fluorescein isothiocyanate diluted in distilled water was observed and photographed using a charge-coupled device (CCD) microscopic camera. The obtained images were processed to determine the mixing intensity at different Reynolds numbers. The standard deviation (σ) of the fluorescence indicates the mixing completeness, which was calculated along the width of the channel at various locations downstream from the channel inlet. The value of σ = 0.5 indicates unmixed streams and 0 is for complete mixing. It is found that the two new designs have a standard deviation of nearly 0.05. Additionally, complete mixing was observed at the channel outlet as demonstrated by the fluorescence images and the numerical results. However, the location of complete mixing at different positions depends on the Reynolds number, which varies between 0.01 and 50. Good agreement was found between the experiment and the numerical results. A correlation to predict the length scale where complete mixing can be achieved is given in terms of the radius of curvature, the mixing module, and the Reynolds number.http://www.mdpi.com/2072-666X/6/7/953passive micromixersdean vorticesReynolds numbermicrofluidicsLOC
spellingShingle Ala’aldeen Al-Halhouli
Aiman Alshare
Mukeet Mohsen
Maher Matar
Andreas Dietzel
Stephanus Büttgenbach
Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
Micromachines
passive micromixers
dean vortices
Reynolds number
microfluidics
LOC
title Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
title_full Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
title_fullStr Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
title_full_unstemmed Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
title_short Passive Micromixers with Interlocking Semi-Circle and Omega-Shaped Modules: Experiments and Simulations
title_sort passive micromixers with interlocking semi circle and omega shaped modules experiments and simulations
topic passive micromixers
dean vortices
Reynolds number
microfluidics
LOC
url http://www.mdpi.com/2072-666X/6/7/953
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AT mukeetmohsen passivemicromixerswithinterlockingsemicircleandomegashapedmodulesexperimentsandsimulations
AT mahermatar passivemicromixerswithinterlockingsemicircleandomegashapedmodulesexperimentsandsimulations
AT andreasdietzel passivemicromixerswithinterlockingsemicircleandomegashapedmodulesexperimentsandsimulations
AT stephanusbuttgenbach passivemicromixerswithinterlockingsemicircleandomegashapedmodulesexperimentsandsimulations