• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 G
• /
• pp.3268-3270
• /
• 1999

This paper presents the fabrication of a micro electromagnetic flowmeter for liquid flow rate measurement. The flowmeter consists of a silicon flow channel with two electrodes and two permanent magnets. The micro flow channel and the detection electrodes are fabricated by the anisotropic etching of two silicon substrates and the metal evaporation process respectively. If conductive fluid passes through a magnet field, electromotive force is generated and detected by two electrodes. When the flow rate is 2.6 ml/sec, the measured output voltage is 7.4 mV.

• 제어로봇시스템학회논문지
• /
• 제12궈1호
• /
• pp.85-92
• /
• 2006

A new silicon micro flow sensor with multiple temperature sensing elements was proposed and fabricated in considering wide range flow velocity measuring device. Thermal mass flow sensor measures the asymmetry of temperature profile around the heater which is modulated by the fluid flow. A micro mass flow sensor was normally composed of a central heater and a pair of temperature sensing elements around it. A new 2-D wide range micro flow sensor structure with three pairs of temperature sensing elements and a central heater was proposed and numerically simulated by Finite Difference Formulation to confirm the feasibility of the wide flow range sensor structure. To confirm the simulation result, the new flow sensor was fabricated on silicon substrate and the basic flow sensing properties of the sensor were measured.

• International Journal of Vascular Biomedical Engineering
• /
• 제1권2호
• /
• pp.30-35
• /
• 2003

Flow characteristics of blood flow in a micro channel were investigated experimentally using a micro-PIV (Particle Image Velocimetry) velocity field measurement technique. The main objective of this study was to understand the real blood flow in micron-sized blood vessels. The Reynolds number based on the hydraulic diameter of micro-channel for deionized (DI) water was about Re=0.34. For each experimental condition, 100 instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity. In addition, the motion of RBC (Red Blood Cell) was visualized with a high-speed CCD camera. The captured flow images of nano-scale fluorescent tracer particles in DI water were clear and gave good velocity tracking-ability. However, there were substantial velocity variations in the central region of real blood flow in a micro-channel due to the presence of red blood cells.

• 대한기계학회논문집B
• /
• 제33권8호
• /
• pp.573-579
• /
• 2009

A thermal mass air flow sensor, which consists of a micro-heater and thermal sensors on the silicon-nitride thin membrane structure, is micro-fabricated by MEMS processes. Three thermo-resistive sensors, one for the measurement of microheater temperature, the others for the measurement of membrane temperature upstream and downstream of the micro-heater respectively, are used. The micro-heater is operated under the constant temperature difference mode via a real time controller, based on inlet air temperature. Two design models for microfabricated flow sensor are compared with experimental results and confirmed their applicabilities and limitations. The thermal characteristics are measured to find the best flow indicator. It is found that two normalized temperature indicators can be adopted with some advantages in practice. The flow sensor with this control mode can be adopted for wide capability of high speed and sensitivity in the very low and medium velocity ranges.

• Journal of Electrical Engineering and Technology
• /
• 제1권3호
• /
• pp.387-395
• /
• 2006

A review on advanced flow visualization techniques is presented particularly for applications to micro scale heat and mass transport measurements. Challenges, development and applications of micro scale visualization techniques are discussed for the study of heating/evaporating thin films, a heated micro channel, and a thermopneumatic micro pump. The developed methods are (1) Molecular Tagging Fluorescence Velocimetry (MTFV) using 10-nm caged seeding molecules (2) Micro Particle Velocimetry (MPIV) and (3) Ratiometric Laser Induced Fluorescence (LIF) for micro-resolution thermometry. These three methods are totally non-intrusive techniques and would be useful to investigate the temperature and flow characteristics in MEMS. Each of these techniques is discussed in three-fold: (1) its operating principle and operation, (2) its application and measurement results, and (3) its future challenges.

• 센서학회지
• /
• 제9권5호
• /
• pp.334-340
• /
• 2000

본 논문에서는 패러데이의 전자기 유도 법칙을 응용한 마이크로 전자 유량 센서를 제작하였다. 마이크로전자 유량 센서는 열 발생이 없고 빠른 응답 속도를 가지고 있고 압력 손실이 없는 장점을 가지고 있다. 전도성 유체가 영구 자석 자장 내의 유로를 통과할 때, 유속에 비례하는 유도 기 전력이 발생하게 되는데, 발생된 기 전력은 유로 벽에 제작된 전극으로 검출된다. 마이크로 전자 유량 센서는 유로를 가지고 있는 두 장의 실리콘 웨이퍼 기판과 전극, 그리고 두 개의 영구 자석으로 구성되어 있다. 두 장의 실리콘 웨이퍼 기판을 이방성 식각 공정으로 유로를 제작하고, Cr/Au를 증착하여 전극을 제작한다. 제작된 마이크로 전자 유량 센서에 유량을 변화시킬 때, 발생되는 기 전력을 측정한다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.1534-1539
• /
• 2004

This experiment has been carried out to measure the process of droplet formation between water phase fluid(PVA 3%) and organic phase fluid(oil) and vector fields measured by a Dynamic Micro-PIV method in the inside of a droplet while generated. Droplet length controlled by changing flow rate conditions in microchannel. Water-in-oil(W/O) droplets successfully generated at a Y junction and cross microchannel. But oil-in-water(O/W) droplets could not be formed at a Y junction microchannel. That is, PVA 3% flow could not be detached from the PDMS surface and ran parallel with oil flow. When PVA 3% flow rate was constant, droplet length and time period decreased as oil flow rate increased, but droplet frequency increased. When PVA 3% and oil flow rate ratio was constant, droplet length and time period decreased as flow rate increased, but droplet frequency increased. All that case, Standard deviation of droplet formation have less than 5% at averaged droplet length and regular-sized droplets were reproducibly formed.

• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
• /
• pp.44-52
• /
• 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.

• 한국추진공학회지
• /
• 제11권6호
• /
• pp.42-49
• /
• 2007

본 연구에서는 마이크로 추진장치의 개발을 위한 기초연구로 마이크로 노즐의 유동 특성을 분석하였다. 냉가스 추진원리를 이용하였으며, 추진 장치의 노즐 목 직경이 1.0, 0.5, 0.25 mm 인 마이크로 노즐을 방전가공을 이용하여 제작하였다. 판스프링과 스트레인 게이지를 이용한 추력측정장치를 이용하여 추력을 측정하였으며, 대기압 환경과 진공환경에서 마이크로 노즐의 유동특성을 분석하였다. 추진제는 아르곤과 질소를 사용하였으며, 실험 결과를 CFD 결과와 비교하였다. 연구 결과 노즐의 소형화로 인해 점성과 배압에 의한 유동손실이 발생함을 확인할 수 있었다.

• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2007년도 추계학술대회
• /
• pp.114-115
• /
• 2007

As a carrier of malaria and sneak of blood, mosquitoes are regarded as an unpleasant insect. However, there are novel phenomena that happen inside a mosquito. Among them, we focused on the blood sucking function of a female mosquito. The main objective of this study was to investigate the mosquito's pumping mechanism in order to resolve the problem encountered when we inject or transport biologic fluids into a micro-chip. To analyze the pumping mechanism, we visualized the blood sucking process inside a female mosquito. Flow characteristics of blood flow in a proboscis were investigated experimentally using a micro-PIV velocity field measurement technique. The anatomical variation of head, thorax, abdomen which work as pumps and valves, was visualized using the syncrotron X-ray micro-imaging technique.