• 동력기계공학회지
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• 제3권2호
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• pp.13-19
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• 1999

The purpose of the present experimental study is to apply multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to high-speed flow region within a domestic boiler circulation pump. Two different kinds of flow rate($27{\ell}/min,\;19{\ell}/min$)are selected as experimental condition. A volute casing and Impeller made of transparent Polycarbonate were made for the easy access of the illumination laser via fiber optical line and cylinder lens assembly to the measuring region. A CCD camera is syncronized with AOM to acquire clear original particle images. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. The instantaneous and time-mean velocity distribution, velocity profile and kinetic energy are represented quantitatively at the full-scale region for the deeper understanding of the unsteady flow characteristics in a commercial circulation pump.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.288-292
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• 2003

The main purpose of this paper is the development of the system which measures the earing rate of aluminum CAN with the CCD camera. In order to optimize imput image, the image object was segregated and the position of the image grasped. In the pre-processing the edges were detected by the Robert mask after improving the definition of image by the histogram equalization. The height of four each ear and angles which occur due to the characteristics of the aluminum CAN are measured manually with the digital vernier calipers in the industrial ground and in the case of the velocity, these require 30 seconds at least by three times measurement per height of one direction of the aluminum. But it took 0.02 seconds when this system was applied. Therefore this system is proven the satisfactory efficiency and reliability as compared to the control result of in industrial ground.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.6-13
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• 2001

A new GA-3D-PTV technique has been constructed to measure an impinging jet. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. GA (Genetic Algorithm) was used based on one-to-one correspondences in order to take advantage of the combinatorial optimization in tracking the pairs of the whole particles of the two images having a time interval. Two fitness functions were introduced in order to enhance the correspondences of the particles. One was based on a concept of the continuum theory and the other one was based on a minimum distance error. The constructed GA-3D-PTV system was applied in success to the measurement of flow characteristics of the impinging jet.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.166-174
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• 1998

The distribution of oil film thickness in piston were measured by induced fluorescence method. A Xe lamp was used as light source. Coumarine-6 was mixed with oil as the fluorescent dye. Fluorescent signal which is proportional to the oil film thickness was acquired by CCD camera and transmitted to the personal computer as video signal. In order to solve the problem of measurement system, irregular distribution and unstability of light intensity, as well as to know the relationship between the oil film thickness and output signal, three different calibration techniques were used. Motoring and firing tests were performed in a single cylinder research engine with transparent liner. By analyzing the oil film thickness converted from the photographed image, it was observed that each of three piston rings scrapes the oil both upward and downward and oil film thickness is not uniform horizontally at a given piston land. The amount of oil in each land was considerably affected by the engine load. It is thought that the blow-by gas blows the oil down to the crankcase.

• 천문학회보
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• 제42권1호
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• pp.35.1-35.1
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• 2017

We present the characteristics and the performance of the new CCD camera system, SNUCAM-II (Seoul National University CAMera system II) that was installed on the Lee Sang Gak Telescope (LSGT) at the Siding Spring Observatory Australia in 2016. SNUCAM-II consists of a deep depletion chip covering a wide wavelength from $0.3{\mu}m$ to $1.1{\mu}m$ with high sensitivity (QE at 90%). It is equipped with SDSS ugriz filters and 13 medium band width (50nm) filters. On LSGT, SNUCAM-II covers $15.7{\times}15.7arcmin$ FOV at pixel scale of 0.92 arcsec and a limiting magnitude of g = 19.91 AB mag at $5{\sigma}$ with 180s exposure time. SNUCAM-II will enable us to study Spectral Energy Distributions (SEDs) of diverse objects from extragalactic sources to solar objects in the southern hemisphere for research and education activities.

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

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.263-268
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• 2004

The characteristics of Diesel spray droplets, such as the velocity and the diameter were simultaneously measured by using an improved Interferometric Laser Imaging for Droplet Sizing method. The experiments were carried out using an accumulator-type unit injector system and a constant-volume vessel. Two dimensional cross-section photographs of sprays were also taken using a double-pulsed Nd- YAG laser sheet and a linear array CCD camera. As a result, interesting relations between the droplets diameter and the velocity were found.

• 한국공작기계학회논문집
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• 제15권2호
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• pp.30-37
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• 2006

The purpose of this study is to visualize the characteristics of ER fluids as preceding step of developing 3 port ER valves. ER fluids are made with silicone oil and 3 weight fraction starch having hydrous particles. The flow visualization of ER fluids flow is obtained by CCD camera with changing the strength of electric field to ER fluids flow. As the strength of the electric field increases, more clusters in flow are made and these clusters are though to be the reasons of the load flow rate being increased and the outlet flow rate being decreased. The ER Valves and load and outlet flow rate check method are considered to be applied to the fluid power control system.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.352-357
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• 2004

The high speed machining center(HMC) has been widely applied to manufacture a die and machine elements product in industrial field. Because the evaluation for HMC is not sufficiently performed, ineffective machining is occasionally conducted in machining industry. In this study, the dynamic characteristics of newly developed machining center is evaluated under running condition and the machinability is investigated experimentally. Also, the in-process measuring instrument which can measure the tool wear on the machine were developed by using the CCD and exclusive jig and calibration instrument for tool wear measurement.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.925-930
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• 2000

This paper is investigated the entrainment of air into sprays which has significant effects on the combustion efficiency, stability of flame using the air-assisted twin-fluid nozzle in non-burning. The factors which may be expected to affect the entrainment of air by a liquid spray are: Relative velocity of droplet and ambient gas; Drop size and size distribution; Density and other property of the liquid. Here, axial, radial velocity and turbulent kinetic energy of spray droplet was measured with the PIV(Particle Image Velocimetry). Spray characteristics were also visualized using CCD camera. The results indicate that the entrainment rate increases more or less non-linearly with the downstream region.