• 한국가시화정보학회지
• /
• 제1권2호
• /
• pp.47-51
• /
• 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.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1045-1046
• /
• 2010

• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2002년도 마이크로/바이오 가시화기술부문 학술강연회
• /
• pp.79-84
• /
• 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.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2006년도 제27회 추계학술대회논문집
• /
• pp.15-18
• /
• 2006

최근 미소기전시스템(MEMS)를 개발함에 있어 마이크로 크기의 유동가시화는 중요한 문제이다. 특히 유체와 고체표면의 상호작용에 있어 표면의 친수성과 소수성의 성질은 미소유체를 조절 가능케 하는 핵심적인 역할이다. 본 연구에서는 마이크로 채널 내 표면을 개질하여 친수성 및 소수성의 벽면 경계조건 습윤도를 측정하였고, 또한 micro-PIV를 이용하여 벽면 근처에서의 속도 분포를 분석하였다.

• 한국가시화정보학회지
• /
• 제5권1호
• /
• pp.43-48
• /
• 2007

Micro-PIV(particle image velocimetry) has been widely used to measure the velocity of micro flow. Although this micro-PIV method can give accurate 2D instantaneous velocity information of mea-surement plane, it cannot resolve the out of plane component of velocity vectors. Lots of the micro fluidic devices generate three-dimensional flow and 3D measurement of velocity is useful to understand the physics of micro flow phenomena. In this study, we constructed stereoscopic micro-PIV(SMPIV) system and applied this method to the impinging micro jet flow. The results show that this method can produce accu-rate 3D reconstruction of micro jet flow.

• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2003년도 추계학술대회 논문집
• /
• pp.87-90
• /
• 2003

In this paper, flow characteristics of plasma flow in a micro-tube were investigated experimentally using Micro-PIV. For comparision, the experiments were repeated for DI-water instead of plasma. Both velocity profiles of Plasma and DI-water are well agreed with the theoretical velocity distribution of newtonian fluid. We also carried out generating plasma-in-oil droplet formation at a Y-junction microchannel. In order to clarify the hydrodynamic aspects involved in plasma droplet formation. Rhodamin B were mixed with plasma only for visualization of plasma droplet.

• 대한기계학회논문집B
• /
• 제28권9호
• /
• pp.1015-1021
• /
• 2004

Micro-resolution Particle Image Velocimetry(Micro-PIV) was used to measure the flow in a micro-branch(Micro-Bypass). In this paper, effects of particle lump at the tip of a Micro-branch and difficulties of Micro-PIV measurements for microfluidics with branch passage were described. Micro-bypass was composed of a straight channel(200(100)${\mu}$m width ${\times}$ 80${\mu}$m height) and two branches which has 100(50)${\mu}$m width ${\times}$ 80${\mu}$m height. One of branches was straight and the other was curved. Experiments were performed at three regions along streamwise direction(entrance, middle and exit of branch) and five planes along vertical direction (0, ${\pm}$10, ${\pm}$20 ${\mu}$m) for the range of Re=0.24, 1.2, 2.4. Numerical simulation was done to compare with the measurements and understand the effects of particle lump at the tip of branch. And another fluid(3% poly vinyl Alcohol aqueous solution) were adapted for this study, so there were no particle sticking. In this case, we could get velocity difference between straight and curved branches.

• 한국가시화정보학회지
• /
• 제8권3호
• /
• pp.22-28
• /
• 2010

In the present study, we performed the velocity field measurement in a microchannel using a focal length variable micro liquid lens. The liquid lens is used as a beam expander in a micro-PIV system to acquire the scatter image of the seeded particle. A thin film-type micro liquid lens was made of PDMS material and it was attached on top of the 700-micron-wide working fluid supply channel trench. As a result, the focal length and contact angle of the liquid lens changed with variations in applied pressure.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 춘계학술대회논문집
• /
• pp.585-588
• /
• 2008

Thermal mixing phenomena in a Y-type microchannel were investigated using a micro-PIV. Two inlet reservoirs of the microchannel were controlled individually so that the characteristics of thermal mixing in the channel with temperature difference were compared with those without the difference. The velocity field in the mixing process was measured using the micro-PIV system that includes an ICCD (Intensified CCD) camera. The mixing area and uniformity were also analyzed. It is observed that the flow fluctuation in spanwise direction is induced by temperature difference, which enhances mixing process in microchannels.

• 대한기계학회논문집B
• /
• 제28권5호
• /
• pp.587-593
• /
• 2004

In this paper, flow characteristics of plasma flow in a micro-tube were investigated experimentally using micro particle image velocimetry(micro-PIV). For comparison, the experiments were repeated for deionized(DI) wale. instead of plasma. Both velocity profiles of plasma and do-ionized water are well agreed with the theoretical velocity distribution of newtonian fluid. We also carried out generating plasma-in-oil droplet formation at a Y-junction microchannel. In order to clarify the hydrodynamic aspects involved in plasma droplet formation, Rhodamine-B were mixed with plasma only for visualization of plasma droplet. With oil as the continuous phase and plasma as the dispersed phase, plasma droplet can be generated in a continuous phase flow at a Y-junction. For given experimental parameters, regular-sized droplets are reproducibly formed at a uniform flow conditions.