The effect of asymmetry on micromixing in curvilinear microchannels

Akgönül, Sarp (2018) The effect of asymmetry on micromixing in curvilinear microchannels. [Thesis]

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The necessity of microscale mixing processes has been tremendously increasing in most of the microsize chemical and biochemical devices during recent years, particularly in the design of lab-on-a-chip and micro-total analysis systems. Different approaches were implemented in the available micromixers in the literature for improving the mixing performance. Due to the absence of any external source, mixing by utilizing passive mixing techniques is more economical. In curvilinear microchannels, which offer effective passive mixing, chaotic advection results in continuous radial perforation of inter-diffusion layer between the fluid streams due to the transverse secondary flows. In this dissertation, the effects of Dean vortices and secondary flows were investigated in asymmetrical polydimethylsiloxane curvilinear rectangular microchannels, which were fabricated by one-step lithography process and had repeated S-shape patterns with a curvature of 280° along the channel. Moreover, the effect of asymmetry was assessed by comparing the mixing results with symmetrical microchannels. Mixing performance was analyzed by using NaOH and phenolphthalein solutions as mixing fluids, which entered from the channel inlets. According to the results, the significant effects of stretching and contracting motion of Dean vortices revealed themselves above a certain Dean number value, thereby making the asymmetrical microchannel outperform the symmetrical channel in the mixing performance. Below this threshold, the symmetrical microchannel was observed to be superior to the asymmetrical microchannel.
Item Type: Thesis
Uncontrolled Keywords: Passive mixing. -- Chaotic advection. -- Dean vortices. -- Curvilinear PDMS microchannels. -- Asymmetrical microchannels. -- Pasif karışma. -- Kaotik adveksiyon. -- Dean vortisleri. -- Dönel PDMS mikrokanallar. -- Asimetrik kanallar.
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ163.12 Mechatronics
Divisions: Faculty of Engineering and Natural Sciences > Academic programs > Mechatronics
Faculty of Engineering and Natural Sciences
Depositing User: IC-Cataloging
Date Deposited: 11 Oct 2018 08:57
Last Modified: 26 Apr 2022 10:26

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