• Title/Summary/Keyword: PIV Microfluidic

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PIV measurements of a microfluidic elements fabricated in a plastic chip (플라스틱 미소유체요소 내부유동의 PIV 측정)

  • Lee, In-Won;Choi, Jay-Ho;Lee, In-Seop
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.400-404
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    • 2001
  • A micro-PIV(particle image velocimetry) measurement has been conducted to investigate flow fields in such microfluidic devices as microchannels and micronozzle. The present study employs a state-of-art micro-PIV system which consists of epi-fluorescence microscope, 620nm diameter fluorescent seed particles and an 8-bit megapixel CCD camera. Velocity vector fields with a resolution of $6.7\times6.7{\mu}m$ has been obtained, and the attention has been paid on the effect of varying measurement conditions of particle diameter and particle concentration on the resulting PIV results. In this study, the microfluidic elements were fabricated on plastic chips by means of MEMS processes and a subsequent molding process. Flow fields in a variety of microchannels as well as micronozzle have been investigated.

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Measurements of a microchannel flow using micro-PIV

  • Lee Inwon;Choi Jayho;Lee In-Seop
    • 한국가시화정보학회:학술대회논문집
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    • 2001.12a
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    • pp.44-52
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    • 2001
  • A micro-PIV(particle image velocimetry) measurement has been conducted to investigate flow fields in such microfluidic devices as microchannels and micronozzle. The present study employs a state-of-art micro-PIV system which consists of epi-fluorescence microscope, 620nm diameter fluorescent seed particles and an 8-bit megapixel CCD camera. Velocity vector fields with a resolution of $6.8\;\times\;6.8{\mu}m$ has been obtained, and the attention has been paid on the effect of varying measurement conditions of particle diameter and particle concentration on the resulting PIV results. In this study, the microfluidic elements were fabricated on plastic chips by means of MEMS processes and a subsequent molding process. Flow fields in a variety of microchannels as well as micronozzle have been investigated.

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Three-dimensional Flow Structure inside a Plastic Microfluidic Element (미소유체요소 내부유동의 3차원 측정 및 수치해석)

  • Lee Inwon;An Kwang Hyup;Nam Young Sok;Lee In-seop
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.419-422
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    • 2002
  • A three-dimensional inlet flow structure inside a microfluidic element has been investigated using a micro-PIV(particle image velocimetry) measurement as well as a numerical analysis. The present study employs a state-of-art micro-PIV system which consists of epi-fluorescence microscope, 620nm diameter fluorescent seed particles and an 8-bit megapixel CCD camera. For the numerical analysis, a commercial software CFD-ACE+(V6.6) was employed for comparison with experimental data. Fixed pressure boundary condition and a 39900 structured grid system was used for numerical analysis. Velocity vector fields with a resolution of $6.7{\times}6.7{\mu}m$ has been obtained, and the attention has been paid on the effect of varying measurement conditions of particle diameter and particle concentration on the resulting PIV results. In this study, the microfluidic elements were fabricated on plastic chips by means of MEMS processes and a subsequent melding process.

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Microfluidic Method for Measurement of Blood Viscosity based on Micro PIV (Micro PIV 를 기반한 혈액 점도 측정 기법)

  • Hong, Hyeonji;Jung, Mirim;Yeom, Eunseop
    • Journal of the Korean Society of Visualization
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    • v.15 no.3
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    • pp.14-19
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    • 2017
  • Increase of blood viscosity significantly changes the flow resistance and wall shear stress which are related with cardiovascular diseases. For measurement of blood viscosity, microfluidic method has proposed by monitoring pressure between sample and reference flows in the downstream of a microchannel with two inlets. However, it is difficult to apply this method to unknown flow conditions. To measure blood viscosity under unknown flow conditions, a microfluidic method based on micro particle image velocimetry(PIV) is proposed in this study. Flow rate in the microchannel was estimated by assuming velocity profiles represent mean value along channel depth. To demonstrate the measurement accuracy of flow rate, the flow rates measured at the upstream and downstream of a T-shaped microchannel were compared with injection flow rate. The present results indicate that blood viscosity could be reasonably estimated according to shear rate by measuring the interfacial width and flow rate of blood flow. This method would be useful for understanding the effects of hemorheological features on the cardiovascular diseases.

Micro-PIV Analysis of Electro-osmotic Flow inside Microchannels (마이크로 채널 내부 전기삼투 유동에 대한 PIV유동 해석)

  • Kim Yang-Min;Lee Sang-Joon
    • Journal of the Korean Society of Visualization
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    • v.1 no.2
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    • pp.47-51
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    • 2003
  • Microfluidic chips such as lab-on-a-chip (LOC) include micro-channels for sample delivery, mixing, reaction, and separation. Pressure driven flow or electro-osmotic flow (EOF) has been usually employed to deliver bio-samples. Having some advantages of easy control, the flow characteristics of EOF in microchannels should be fully understood to effectively control the electro-osmotic pump for bio-sam-pie delivery. In this study, a micro PIV system with an epifluorescence inverted microscope and a cooled CCD was used to measure velocity fields of EOF in a glass microchannel and a PDMS microchannel. The EOF velocity fields were changed with respect to electric charge of seeding particles and microchannel materials used. The EOF has nearly uniform velocity distribution inside the microchannel when pressure gradient effect is negligible. The mean streamwise velocity is nearly proportional to the applied electric field. Glass microchannels give better repeatability in PIV results, compared with PDMS microchannels which are easy to fabricate and more suitable for PIV experiments.

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PIV Measurements of the Pressure Driven Flow Inside a T-Shaped Microchannel (T형 마이크로채널 내부 압력구동 유동의 PIV 계측)

  • Choi Jayho;Lee In-Seop
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.423-426
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    • 2002
  • A custom micro-PIV optics assembly has been used to measure the flow field inside a T-shaped microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of $420,\;40,\;60{\mu}L/hr$. The microchannels are fabricated with PDMS with a silicon mold, then $O_2-ion$ bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results show PIV results with vector-to-vector distances of $2{\mu}m$ with 32 pixel-square interrogation windows at $50{\%}$ overlap.

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Visualization of micro-interfacial conditions using Micro PIV

  • OKAMOTO Koji;SHINOHARA Kyosuke;SUGII Yasuhiko
    • 한국가시화정보학회:학술대회논문집
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    • 2004.12a
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    • pp.111-118
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    • 2004
  • A new micro-resolution PIV (Particle Image. Velocimetry) has been developed. To investigate transient phenomena in a microfluidic device, Dynamic micro-PIV system was realized by combining a high-speed camera and a CW(Continuous Wave) laser. The technique was applied to a micro-counter-current flow, consisting of water and butyl acetate. The velocity fields of water in the micro counter-current flow were visualized for a time resolution of 500 $\{mu}s$ and a spatial resolution of 2.2 x 2.2 $\{mu}m$. Using the Dynamic micro-PIV technique, the vortex-like motions of fluorescent particles at the water-butyl acetate interface were captured clearly

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Micro-PIV measurement of internal flow in a micro droplet

  • KINOSHITA Haruyuki;KOBAYASHI Toshio;OSHIMA Marie
    • 한국가시화정보학회:학술대회논문집
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    • 2004.12a
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    • pp.141-145
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    • 2004
  • Visualization and PIV measurements of the symmetrical recirculation flow in a nanoliter-sized droplet have been performed using the micro PIV system. The airflow sweeps over the nanoliter-sized liquid droplet fixed in a microchannel and the frictional force drags the liquid on the round interface, which causes the symmetrical recirculation flow in the droplet. The internal recirculation flow in the droplet has been visualized and measured successfully. The results of micro PIV measurement show the maximum speed of the recirculation flow is up to 10 mm/s. The high-speed recirculation can enhance a stirring effect and generate strong shear in the droplet, resulting in acceleration of mixing.

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Micro- PIV Measurements of Microchannel Flows and Related Problems (마이크로 채널 내부 유동의 Micro-PIV측정과 제반 문제점)

  • Lee Sang-Joon;Kim Guk-bae
    • 한국가시화정보학회:학술대회논문집
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    • 2002.04a
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    • pp.79-84
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    • 2002
  • Most microfluidic devices such as heat sinks for cooling micro-chips, DNA chip, Lab-On-Chip, and micro pumps etc. have microchannels of various size. Therefore, the design of practical microfluidics demands detail information on flow structure inside the microchannels. However, detail velocity field measurements are rare and difficult to carry out. In addition, as the microfluidics expands, accurate understanding of microscale transport phenomena becomes very important. In this research, micro-PIV system was employed to measure the velocity fields of flow inside a micro-channel. We carried out PIV measurements for several microchannels with varying channels width, inlet and outlet shape, filters, CCD camera and ICCD camera, etc. For effective composition of micro-PIV system, first of all, it is essential to understand optics related with micro-imaging of particles and the particle dynamics encountered in micro-scale channel flows. In addition, it is necessary to find the optimal condition for given experimental environment and? micro-scale flow to be investigated. The problems encountered in measuring velocity field of micro-channel flows are discussed in this paper.

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Flow Visualization of the Flow inside the Droplet Passing through a Straight and a Diverging Channel (직선채널과 확대채널에서의 액적 내부 유동 가시화)

  • Jin, Byung-Ju;Kim, Young-Won;Yoo, Jung-Yul
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.71-76
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    • 2007
  • Flow visualization of a droplet passing through a straight channel and a diverging channel has been carried out using micro-PIV. Diverging channel is frequently used in lab-on-a-chip and microfluidic devices, where flow pattern inside the droplet passing is quite different from that through a straight channel. In the present study, we visualized the droplet flow in three different regions. The first region is where the droplet has a wide contact area with the channel wall, the second region is characterized with a narrow contact area and the third region is where droplet is detached from the channel wall. Visualization results show that the internal flow inside the droplet passing through the straight channel moves in the opposite direction to the droplet velocity in the near wall exhibiting complex flow patterns. But in the diverging channel the internal flow inside the droplet moves in the same direction as the droplet velocity due to the shear induced by oil phase flow exhibiting rather simple flow pattern.

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