Static Chaos Microfluid Mixers Using Microblock-Induced Alternating Whirl and Microchannel-Induced Lamination

2003 ◽  
Author(s):  
Sunghwan Chang ◽  
Young-Ho Cho
Keyword(s):  
Pressure Drop ◽  
Flow Channel ◽  
Mixing State ◽  
Alternating Direction ◽  
Micro Total Analysis Systems ◽  
Total Analysis ◽  
Visualization Experiments

We characterize two types of noble static chaos microfluid mixers for the applications to Micro Total Analysis Systems (μTAS): an AW-type microfluid mixer, having a series of microblocks along a flow channel for generating alternating direction whirl (AW) flows, and an AWL-type microfluid mixer, coupling the AW-type microfluid mixers with divided microchannels for generating lamination flows between the alternating whirl flows. For generating whirling flow in microchannels, we design rotating block geometry in microchannels. For chaos mixing, we suggest alternating-directional whirling flows in microchannels. AW, AWL-type microfluid mixers are made of PDMS (Polydimethylsiloxane). We quantify mixing state using phenolphthalein visualization experiments and measure pressure drop through microfluid mixers.

Three-Dimensional CFD Model of Pressure Drop in µTAS Devices in a Microchannel

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Damena D. Agonafer ◽  
J. Yeom ◽  
M. A. Shannon
Keyword(s):  
Pressure Drop ◽  
Figure Of Merit ◽  
Flow Resistance ◽  
Three Dimensional ◽  
Design Rule ◽  
Dynamics Model ◽  
Enhance Heat Transfer ◽  
Micro Total Analysis Systems ◽  
Total Analysis ◽  
Adsorption Desorption

Microposts are utilized to enhance heat transfer, adsorption/desorption, and surface chemical reactions. In a previous study [Yeom et al., J. Micromech. Microeng., 19, p. 065025 (2009)], based in part on an experimental study, an analytical expression was developed to predict the pressure drop across a microchannel filled with arrays of posts with the goal of fabricating more efficient micro-total analysis systems (µTAS) devices for a given pumping power. In particular, a key figure of merit for the design of micropost-filled reactors, based on the flow resistance models was reported thus providing engineers with a design rule to develop efficient µTAS devices. The study did not include the effects of the walls bounding the microposts. In this paper, a three-dimensional computational fluid dynamics model is used to include the effects of three-dimensionality brought about by the walls of the µTAS devices that bound the microposted structures. In addition, posts of smaller size that could not be fabricated for the experiments were also included. It is found that the two- and three-dimensional effects depend on values of the aspect ratio and the blockage ratios. The Reynolds number considered in the experiment that ranged from 1 to 10 was extended to 300 to help determine the range of Re for which the FOM model is applicable.

scholarly journals Glass based Micro Total Analysis Systems: Materials, Fabrication methods, and Applications

2021 ◽  
pp. 129859
Author(s):  
Tao Tang ◽  
Yapeng Yuan ◽  
Yaxiaer Yalikun ◽  
Yochiroh Hosokawa ◽  
Ming Li ◽  
...  
Keyword(s):  
Micro Total Analysis Systems ◽  
Total Analysis

scholarly journals The Effects of the PEM Fuel Cell Performance with the Waved Flow Channels

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Yue-Tzu Yang ◽  
Kuo-Teng Tsai ◽  
Cha’o-Kuang Chen
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Gas Flow ◽  
Gas Diffusion ◽  
Flow Channel ◽  
Proton Exchange ◽  
Electrical Performance ◽  
Wave Number ◽  
Gap Size ◽  
Fuel Cell Performance

The objective of this study is to use a new style of waved flow channel instead of the plane surface channel in the proton exchange membrane fuel cell (PEMFC). The velocity, concentration, and electrical performance with the waved flow channel in PEMFC are investigated by numerical simulations. The results show that the waved channel arises when the transport benefits through the porous layer and improves the performance of the PEMFC. This is because the waved flow channel enhances the forced convection and causes the more reactant gas flow into the gas diffusion layer (GDL). The performance which was compared to a conventional straight gas flow channel increases significantly with the small gap size when it is smaller than 0.5 in the waved flow channel. The performance is decreased at the high and low velocities as the force convection mechanism is weakened and the reactant gas supply is insufficient. The pressure drop is increased as the gap size becomes smaller, and the wave number decreases. (gap size)δ> 0.3 has a reasonable pressure drop. Consequently, compared to a conventional PEMFC, the waved flow channel improves approximately 30% of power density.

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