• Title/Summary/Keyword: PIV: 입자영상유속계

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Simple Image-Separation Method for Measuring Two-Phase Flow of Freely Rising Single Bubble (상승하는 단일 버블 이상유동의 PIV 계측을 위한 영상분리기법)

  • Park Sang-min;Jin Song-wan;Kim Won-tae;Sung Jae-yong;Yoo Jung-Yul
    • 한국가시화정보학회:학술대회논문집
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    • 2002.11a
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    • pp.7-10
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    • 2002
  • A novel two-phase PIV algorithm using a single camera has been proposed, which introduces a method of image-separation into respective phase images, and is applied to freely rising single bubble. Gas bubble, tracer particle and background each have different gray intensity ranges on the same image frame when reflection and dispersion in the phase interface are intrinsically eliminated by optical filters and fluorescent material. Further, the signals of the two phases do not interfere with each other. Gas phase velocities are obtained from the separated bubble image by applying the two-frame PTV. On the other hand, liquid phase velocities are obtained from the tracer particle image by applying the cross-correlation algorithm. Moreover, in order to increase the SNR (signal-to-noise ratio) of the cross-correlation of tracer particle image, image enhancement is employed.

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

  • 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.

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

  • Yu, Cheong-Hwan;Kim, Hyoung-Bum
    • Journal of the Korean Society of Visualization
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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.

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

  • Im, Yu-Cheong;Seo, Min-Sik;Lee, Young-Ho
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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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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A Study on Flow and Efficiency Characteristics in Guide Vane of Diffuser Pump Using PIV Measurement (PIV 계측을 이용한 디퓨져펌프의 정익에서의 성능과 유동특성에 관한 연구)

  • Kim, J. H.;Choi, M. S.;Kim, J. G.;Lee, Young-Ho
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.29-35
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    • 2000
  • 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.

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

  • Lee, Sang-Joon
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.145-146
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    • 2006
  • Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the 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 engineering 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 most complicated nano- and bio-fluidic phenomena. In this presentation, 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 will be introduced as a blue ocean strategy.

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Flow Characteristics of Guide Vane of Diffuser Pump by PIV Measurement (PIV계측에 의한 디퓨져펌프 안내깃에서의 유동특성)

  • Kim, J.H.;Choi, J.W.;Kim, M.Y.;Lee, H.;Lee, Young-Ho
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.391-396
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    • 2000
  • The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within a diffuser pump. Various different kinds of clearance were selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors was implemented with direct calculation of correlation coefficients. Fine optical setup important in PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Various flow patterns are represented quantitatively at the stator passages.

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An experimental analysis of the fluid flow in an automobile HVAC system using a PIV technique (PIV기법을 이용한 차량용 공조 시스템 내부유동에 대한 실험적 연구)

  • Ji, Ho-Seong;Kim, Bo-Ram;Lee, Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.92-96
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    • 2007
  • Internal flow characteristics for an automobile HVAC have been investigated using a high-resolution PIV technique. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera($2K\;{\times}\;2K$), optics and a synchronizer. An automobile HVAC module was used directly. Only the casing was remodeled transparently for capturing flow image and laser sheet beam illumination. Time-averaged velocity field were measured in three temperature control mode. For three temperature control modes, the internal flow characteristics for an automobile HVAC system were evaluated from PIV results..

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An Experimental Investigation on Flow Field in a Pipe with Sinusoidally Wavy Surface by PIV (PIV를 이용한 3차원 파형관 내부 유동장의 실험적 연구)

  • 김성균
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.4
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    • pp.368-373
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    • 2004
  • A flow field in a passage with periodically converging-diverging cross-section is investigated experimentally by PIV measurement. A tube with a sinusoidally wavy cross section is one of several devices employed for enhancing the heat and mass transfer efficiency due to turbulence promotion and unsteady vortical motion. While the numerical flow visualization results have been limited to the fully developed cases, existing experimental results of this flow were simple qualitative ones by smoke or dye streak test. Therefore, the main purpose of this study is to produce quantitative flow data for fully developed and transient flow regime by the Correlation Based Correction PIV (CBC PIV) and to conjecture the analogy between flow characteristics and heat transfer enhancement with low pumping power. Another purpose of this paper is to examine the onset position of the transition and the global mixing, which results in transfer enhancement. At Re=2000, evidences of the global mixing are captured at 2.5 wavy module through the variation of RMS values and instantaneous velocity plot.

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

  • Lee, Sang-Joon
    • Journal of the Korean Society of Visualization
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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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