• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.437-442
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• 2015

본 연구에서는 SI 엔진의 정상유동장치에서 충격식 스월미터로 측정한 스월비와 PIV(입자영상유속계) 속도장을 적분하여 구한 스월비를 비교 고찰하였다. PIV 속도장으로부터 스월비를 산출하는 방식에 있어서는 토크를 실린더의 기하학적 중심과 스월 중심에서 각각 계산하여 비교하였다. 또한, 정상유동장치에서 토크의 측정 위치를 변화하여 그에 따른 영향도 고찰하였다. 그 결과, 와류가 안정화되지 못한 상류에서는 충격식 스월미터의 측정값이 PIV로 측정한 값보다 크게 나타났다. PIV 측정에 있어서는 유동 상류에서 실린더 중심을 기준으로 산출한 값이 스월 중심으로 산출한 값보다 작게 나타났다. 측정위치가 하류로 이동하여 스월이 안정화되면서 측정방법에 따른 차이점이 줄어든다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.125-128
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• 2004

Chemical Mechanical Polishing(CMP) in semiconductor production is characterized its output property by Removal Rate(RR) and Non-Uniformity(NU). Some Previous works shows that RR is determined by production of pressure and velocity and NC is also largely affected by velocity of flow-field during CMP. This study is about the direct measurement of velocity of slurry during CMP and reconstruction whole flow-field by Particle Image Velocimetry(PIV) Techniques. Typical PIV system is tuned adequately for inspecting CMP and Slurry Flow-field is measured by changing both Pad RPM and Carrier RPM. The results show that velocity is majorly determined not by Carrier RPM, but by Pad RPM.

• 한국공작기계학회논문집
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• 제15권1호
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• pp.56-62
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• 2006

An experimental investigation was performed to study the characteristics of ER(Electro-Rheological) fluid flow in a horizontal rectangular tube with or without D.C voltage. To determine some characteristics of the ER flow, 2D PIV(Particle Image Velocimetry) technique is employed for velocity measurement. This research found the mean velocity distribution with 0kV/mm, 1.0kV/mm and 1.5kV/mm for Re = 0, 0.62, 1.29 and 2.26. When the strength of the electric field increased, the cluster of ERF are clearly strong along the test tube and the flow rate decreased. In this study, the rheology of ER fluid stagnating or flowing through a dispersion meter will be investigated by PIV method. And then the ER effect, which appears at the ER valves and their appliance will be visualized.

• 한국산학기술학회논문지
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• 제3권4호
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• pp.251-256
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• 2002

폴리머용액의 특성확산시간은 낙구의 종말속도를 측정함으로써 결정할 수 있다. 확산시간은 폴리머 용액의 농도가 증가할수록 증가한다. 입자영상유속장치 (PIV)를 이용하여 구주위의 유동현상을 가시화 하였다. 2000 ppm의 경우 30 초 간격으로 떨어뜨렸을때의 속도가 0초( 처음)나 40초후, 50초후에 떨어뜨렸을때와 비교하여 가장 크게 나타났다. 뉴톤 유체에서는 낙구의 전방과 후방에서 구주위의 유동장이 동일하게 나타났다.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1799-1808
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• 2004

Knowledge of airflow characteristics in nasal cavity is essential to understand the physiological and pathological aspects of nasal breathing. Several studies have utilized physical models of the healthy nasal cavity to investigate the relationship between nasal anatomy and airflow. Since the final goal of these works is their contribution to the diagnosisand treatment of nasal diseases, the next step on this topic is naturally studies for disordered nasal cavities. In this paper, as the first application, airflows in the normal and abnormal nasal cavities with adenoid vegetation are investigated experimentally by PIV, and comparisons of both cases are appreciated. Dense CT data and careful treatment of model surface under the ENT doctor's advice provide more sophisticatedcavity model. The CBC PIV algorithm with window offset is used for PIV flow analysis. Average and RMS distributions are obtained for inspirational and expirational nasal airflows. Airflow characteristics that are related with the abnormalities in nasal cavity are presented.

• 한국유체기계학회 논문집
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• 제5권1호
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• pp.7-12
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• 2002

As the first step to investigate the fundamental mechanism of a dispersed two-phase flow, we studied the detailed interactions between bubble or particle motion and flow around it. Experiments were carried out with a rising bubble or particle in stagnant water in a vertical pipe. Particles with different densities, and/or different shapes were used for comparison with a bubble. We adopted 3D-PTV (Three-Dimensional Particle Tracking Velocimetry) for measuring the bubble or particle motions, and PIV (Particle Image Velocimetry) for measuring the water flow simultaneously (Hybrid PIV). The experimental results showed that the oblate spheroidal solid particle rose along the longer axis direction at the point that the inclination of the longer axis reached the maximum, and the inclination direction changed after moving. The bubble moved to the direction that the spheroid's projected width grew up to the largest, and the minor axis of the oblate spheroidal body of the bubble was parallel to the moving direction. The trajectory of the center of the particle/bubble which was measured with 3D-PTV, was marked on the section (x-y) of the pipe. It exhibited the pattern of the particle/bubble motion.

• 한국해양공학회지
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• 제18권3호
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• pp.1-7
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• 2004

Flaw visualization and velocity field measurement methods have practical applications in the various fluid engineering fields, such as mechanics, ships, and heat fluids. In this study, the basic principles and theoretical methods are used to establish an application technique of Particle Imae Velocimetry(abbreviated to PIV below). Accordingly, the measured results of velocity field distribution of a section inside the Circulating Water Channel (abbreviated to CWC below) are computed using the PIV is presented. The uniformity of velocity distribution of the section in CWC is confirmed, by comparing this PIV data with the existing current meter data. Also, in order to measure the flaw fields of surroundings of 2-dimensional cylinder in the CWC, the flaw visualization technique using the PIV is applied.

• 대한기계학회논문집B
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• 제28권3호
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• pp.365-370
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• 2004

Simultaneous measurement with PLIF(Planar Laser-Induced Fluorescence) and Stereo-PIV(Stereo Particle Image Velocimetry) was performed to investigate the structural characteristics of flow field in Rushton Turbine Mixer. Instantaneous 3D velocity fields are measured by two 2K${\times}$2K CCD cameras focused on an object plane with the angular displacement methods while the concentration fields are obtained through the measurement of the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. Finally, the spatial structures of turbulent flow around Rushton turbine were identified by the calculation of synchronized data of the velocity field and concentration field.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.694-699
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• 2003

Simultaneous measurement with PLIF(Planar Laser-Induced Fluorescence) and Stereo-PIV(Stereoscopic Particle Image Velocimetry) was performed to investigate the structural characteristics of flow field in Rushton Turbine Mixer. Instantaneous 3D velocity fields are measured by two 2K ${\times}$ 2K CCD cameras focused on an object plane with the angular displacement methods while the concentration fields are obtained through the measurement of the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. Finally, the spatial structures of turbulent mixing around Rushton turbine were identified by the calculation of cross-correlation fields between the velocity and concentration field.

• 한국항공우주학회지
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• 제44권6호
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• pp.477-483
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• 2016

본 연구는 Particle Image Velocimetry(PIV) 기법을 이용하여 마하수 2.96의 평판에 대해 층류, 천이, 난류 경계층의 속도 분포를 측정하였다. Schlieren 가시화 기법과 PIV 기법을 이용하여 앞전에서 발생한 경사 충격파가 평판 위의 유동장에 영향을 주는지 확인하였다. 층류 경계층의 경우, 실험에서 측정한 속도 분포가 압축성 Blasius 속도 분포를 만족하였다. 천이 경계층의 속도 분포는 벽면 부근부터 이론적인 난류 속도 분포로 변했으며, Re = $1.41{\times}10^6$에서 천이가 시작되었다. 난류 경계층 영역에서는 압축성 효과를 고려한 Van Driest 변환 속도가 비압축성 로그 법칙을 만족하였다. 또한 로그 구간이 끝나는 위치($y/{\delta}{\approx}0.28$)가 비압축성 난류 경계층($y/{\delta}{\approx}0.2$)에 비해 벽면에서 더 멀어진 것을 확인하였다.