• Title/Summary/Keyword: Helical microchannel

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CFD analysis of geometric parameters that affect dean flow in a helical microchannel

  • Prasad, Bibin;Kim, Jung Kyung
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.10
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    • pp.1269-1274
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    • 2014
  • Due to the presence of Dean flow in curved ducts, helical channels have drawn attention recently because of the practical industrial applications. The manipulation of fluids through microfluidic devices is widely used in many scientific and industrial areas. In the present study, numerical simulations were performed on a helical microchannel to predict the impact of different design parameters that affect Dean flow. Important geometric parameters such as the channel cross section, pitch, radius of curvature, and number of turns were considered for the analysis. The study also incorporates the effect of varying flow rate on Dean flows. It was found from the simulation results that microchannel cross section and pitch have a significant impact on maintaining the Dean flow, compared to the radius of curvature, number of turns, and flow rate.

Development of a Barrier Embedded Chaotic Micromixer (배리어가 포함된 카오스 마이크로 믹서의 개발)

  • 김동성;이석우;권태헌;이승섭
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.1
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    • pp.63-69
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    • 2004
  • It is of great interest to enhance mixing performance in a microchannel in which the flow is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved in this laminar flow regime. In this regard, we present a new chaotic passive micromixer, named Barrier Embedded Micromixer (BEM), of which the mixing mechanism is based on chaotic flows. In BEM, chaotic flow is induced by periodic perturbation of the velocity field due to periodically inserted barriers along the channel wall while a helical type of flow is obtained by slanted grooves on the bottom surface of the channel in the pressure driven flow. To experimentally compare the mixing performance, a T-microchannel and a microchannel with only slanted grooves were also fabricated. All microchannels were made of PDMS (Polydimethylsiloxane) from SU-8 masters that were fabricated by conventional photolithography. Mixing performance was experimentally characterized with respect to an average mixing intensity by means of color change of phenolphthalein as pH indicator. It was found that mixing efficiency decreases as Re increases for all three micromixers. Experimental results obviously indicate that BEM has better mixing performance than the other two. Chaotic mixing mechanism, suggested in this study, can be easily applied to integrated microfluidic systems , such as Micro-Total-Analysis-System, Lab-on-a-chip and so on.

Development of a Three-Dimensional Barrier Embedded Kenics Micromixer by Means of a Micro-Stereolithography Technology (마이크로 광 조형기술을 이용한 3차원의 배리어가 포함된 케닉스 마이크로 믹서의 개발)

  • Lee In Hwan;Kwon Tai Hun;Cho Dong-Woo;Kim Dong Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.6 s.237
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    • pp.904-912
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    • 2005
  • The flow in a microchannel is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved. In this regard, we developed a novel chaotic micromixer, named Barrier Embedded Kenics Micromixer (BEKM). In the BEKM, the higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: (i) splitting/reorientation by helical elements inside the microchannel and (ii) stretching/folding via periodically located barriers on the channel wall. The fully three-dimensional geometry of BEKM was realized by a micro-stereolithography technology, in this study, along with a Kenics micromixer and a circular T-pipe. Mixing performances of three micromixers were experimentally characterized in terms of an average mixing color intensity of phenolphthalein. Experimental results show that BEKM has better mixing performance than other two micromixers. Chaotic mixing mechanism, proposed in this study, could be integrated as a mixing component with Micro-Total-Analysis-System, Lab-on-a-chip and so on.

Analysis of Mining Performance and Flow Measurement Inside a Micro Mixer (마이크로 혼합기 내의 유동 계측 및 혼합 특성 해석)

  • Sung Jaey-ong;Lee In-won;Kim Byoung-Gyun;Yoon Eui-sik;Lee In-Seop
    • 한국가시화정보학회:학술대회논문집
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    • 2002.11a
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    • pp.45-48
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    • 2002
  • To investigate the flow related to the mixing, micro PIV measurements were performed in the middle plane of the channel. A passive micro mixer analyzed in this work has been designed in the shape of a three-dimensional microchannel and fabricated with PDMS molding process by KAIST. The mixing performance was evaluated for different flow rates using phenolphthalein and sodium hydroxide solutions. Results show that mixing is enhanced by the increase of flow rate, which yields stronger secondary flows with helical streamlines.

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