• 제목/요약/키워드: PIV

검색결과 1,322건 처리시간 0.06초

액적의 속도 측정을 위한 이색 PIV 알고리즘 연구 (The Study on Two-color PIV Algorithm for a Measurement of Droplet Velocity)

  • 이기형;이창식;오승익
    • 한국분무공학회지
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    • v.4 no.1
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    • pp.13-18
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    • 1999
  • It has been known that spray characteristics have an important effect on the mixture formation and directly influence the engine performances and the emissions. Up to now, the measurement of droplet size is well developed such as PDPA and PMAS though the behavior of small droplets during secondary atomization is not clear. Particle image velocimetry(PIV), a planar measuring technique, is a very efficient tool for studying complicated behavior and a fast and reliable method to track numerous droplets during injection. In this study, two-color scanning PIV is designed to obtain quasi-instantaneous two dimensional velocity data by using he-ion laser, rotating mirror and beam splitter. This PIV method which has high temporal and spatial resolution provides the information about the small complex droplet behavior.

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PIV를 이용한 디퓨저펌프 정익에서의 성능과 유동특성에 관한 연구 (A Study on Flow Characteristics and Efficiency in Guide Vane of Diffuser Pump Using PIV Measurement)

  • 김정환;김범석;김진구;함승덕;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.5
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    • pp.633-640
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    • 2003
  • The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within diffuser pump. Various different kinds of rotational velocity were selected as experimental condition. Optimized cross correlation Identification to obtain velocity vectors is implemented with direct calculation of correlation coefficients. Fine optical setup concerned with PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Variable flow pattern are represented quantitatively at the stator region.

T헝 마이크로채널 연결부 압력구동 유동의 PIV계측 (PIV Measurements of the Pressure Driven Flow Inside a T-Shaped Microchannel Junction)

  • 최제호;이인섭
    • 한국가시화정보학회지
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    • v.1 no.1
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    • pp.75-81
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    • 2003
  • A custom micro-PIV optics assembly has been used to measure the flow fold inside a T-junction of a 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 620 nm 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 2.0, 4.0, 6.0 mL/hr. The micro-channels 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 include PIV data with vector-to-vector distances of 2 $\mu$m with 32 pixel-square interrogation windows at 50$\%$ overlap.

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미세제트 유동의 Stereoscopic micro-PIV측정 (Stereoscopic micro-PIV measurements of jet flow)

  • 유청환;김형범
    • 한국가시화정보학회지
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    • v.5 no.1
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    • pp.43-48
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    • 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.

PIV를 이용한 터빈펌프의 동${\cdot}$정익 속도장 계측 (Measurement of the Velocity field of Rotor-Stator in a Centrifugal Turbine Pump by Using PIV)

  • 임유청;서민식;이영호
    • 유체기계공업학회:학술대회논문집
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    • pp.11-18
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    • 1998
  • The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to rotor-stator region within centrifugal turbine pump. Six different kinds of rpm(120, 500, 1000, 1500, 2000 and 2500) are selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. Fine optical setup deeply concerned with PIV performance is arranged for accurate PIV measurement of high-speed complex flow. The instantaneous and time-mean velocity distribution and velocity profile are represented quantitatively at the rotor and stator region.

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첨단 유동가시화 기법들과 Blue Ocean 전략 (Advanced Flow Visualization Technologies and Blue Ocean Strategy)

  • 이상준
    • 한국가시화정보학회지
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    • v.4 no.2
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    • pp.3-5
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    • 2006
  • Recently, the next-generation advanced flow visualization techniques such as holographic PIV, aynni.c PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced mea-surement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. They would be indispensable in solving complicated thermo-fluid flow problems not only in industrial fields such as automotive, space, electronics, aero- and hydro-dynamics. steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy technology etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe the nano- and bio-fluidic flow phenomena. In this article, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body are introduced as a blue ocean strategy.

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PIV를 이용한 터빈펌프의 동${\cdot}$정익 속도장 계측 (Measurement of the Velocity Field of Rotor-Stator in a Centrifugal Turbine Pump Using PIV)

  • 임유청;서민식;이영호
    • 한국유체기계학회 논문집
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    • v.2 no.1
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    • pp.35-42
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    • 1999
  • The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to rotor-stater region within centrifugal turbine pump. Six different kinds of rpm(120, 500, 1000, 1500, 2000 and 2500) are selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coefficients. Fine optical setup concerned with PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. The instantaneous and time-mean velocity distribution and velocity profile are represented quantitatively at the rotor and stator region.

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PIV에 의한 NACA0012 익 주변의 유동특성 (Flow Characteristics around a NACA0012 Airfoil by PIV)

  • 최민선;조대환;이영호
    • 동력기계공학회지
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    • v.3 no.1
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    • pp.29-37
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    • 1999
  • The flow characteristics of a NACA0012 airfoil was investigated in rectangular water circulating channel. The flow patterns around an airfoil at various angles of attack between $0^{\circ}\;and\;30^{\circ}\;at\;Re=1.91{\times}104$ were visualized and measured with 2-D PIV system and laser sheet illumination. Flow behaviors such as velocity distribution, kinetic energy and flow separation etc. around an airfoil were obtained by means of 2-D PIV system. The behaviors show the difference of flow pattern clearly and separation phenomena become more active with increasing angle of attack.

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PIV에서의 보간기법의 평가에 관한 연구 (A Study on the Evaluation of Interpolation Methods in PIV)

  • 최장운;조대한;최민선;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.4
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    • pp.90-100
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    • 1996
  • To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

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PIV에서의 보간기법의 평가에 관한 연구 (A Study on the Evaluation of Interpolation Methods in PIV)

  • 최장운;조대환;최민선;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.4
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    • pp.412-412
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    • 1996
  • To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.