• Title/Summary/Keyword: 유동 가시화

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Visualization of Internal Flows in the Wall-injected Test Model of a SRM (고체로켓모터 표면분사 시험모델의 유동 가시화)

  • Kim, Do-Hun;Lee, In-Chul;Koo, Ja-Ye;Cho, Yong-Ho;Kang, Moon-Jung;Kim, Yoon-Gon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.3
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    • pp.31-39
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    • 2011
  • The flowfield in a solid rocket motor was simulated at the wall-injection test model, which has a fin-slot grain and submerged nozzle, and visualized by a smoke-wire. The high speed CCD camera captured the visualized images around the nozzle inlet through the grain center port. The vortical tube structure and circumferential flow patterns at the nozzle throat were visualized. The radial momentum transfer caused by the shear-interactions of slot-outlet flow, fin-base flow and grain port flow from upstream worked as the source of these phenomena.

Study on the Vortex Shedding Phenomena Near Free Surface (자유수면 근처에서의 보오텍스 방출 현상에 관한 고찰)

  • Seok-Won Hong;Pan-Mook Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.2
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    • pp.118-131
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    • 1991
  • The effects of free surface on vortex shedding phenomena around a bluff body were studied by both numerical simulation and flow visualization experiments. A vortex method, which approximates the vorticity field as the sum of discrete vortices; was used for the numerical simulation. Flow visualization experiments were performed in the KRISO cavitation tunnel. Hydrogen bubble was used as illumination material. Free surface elevation was also measured during experiments. The hydrodynamic drag and lift were predicted by numerical simulation. The predicted period of vortex shedding was compared with the results of experiments.

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Water-Simulant Facility Installation for the Sodium-Cooled Fast Reactor KALIMER-600 and Global Flow Measurement (소듐냉각고속로 KALIMER-600 축소 물모의 열유동 가시화 실험장치 구축 및 거시 유동장 특성 측정)

  • Cha, Jae-Eun;Kim, Seong-O
    • Journal of the Korean Society of Visualization
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    • v.9 no.4
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    • pp.54-62
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    • 2011
  • KAERI has developed a KALIMER-600 which is a pool-type sodium-cooled fast reactor with a 600MWe electric generation capacity. For a SFR development, one of the main topics is an enhancement of the reactor system safety. Therefore, we have a long-term plan to design the large sodium experimental facility to evaluate the reactor safety and component performance. In order to extrapolate a thermal hydraulic phenomena in a large sodium reactor, the thermal hydraulics phenomena is under investigation in a 1/$10^{th}$ water-simulant facility for the KALIMER-600. In this paper, we shortly described the experimental facility setup and the measurement of the isothermal global flow behavior. For the flow field measurement, the PIV method was used in a transparent Plexiglas reactor vessel model at around $20^{\circ}C$ water condition.

Flow Visualization in Microchannel Using Confocal Scanning Microscope (공초점 주사현미경을 통한 미세 유로에서의 유동 가시화)

  • Chang Jun Keun;Park Sung-Jin;Kim Jung Kyung;Han Dong Chul
    • Journal of the Korean Society of Visualization
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    • v.1 no.1
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    • pp.28-33
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    • 2003
  • This paper presents the visualization method in which 3-dimensional(3D) microchannel flow can be detected using a confocal scanning microscope. By soft-lithography, we fabricated various Bio-MEMS(Micro Electro-Mechanical System) devices such as a disposable microchip for a flow cytometer and a micro-mixer, which have 3D structures. Injecting aqueous fluorescent solution in the microfluidic devices, we measured the flow in a steady state by the confocal scanning microscope. At first, we explain the principle of the confocal scanning microscope. And then we show the results from 3D visualization of microscopic flow structures using the confocal scanning microscope.

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Internal flow visualization of an evaporating droplet placed on heated metal plate (가열된 금속표면에 놓인 증발하는 액적의 내부유동 가시화)

  • Park, Chang-Seok;Lim, Hee-Chang
    • Journal of the Korean Society of Visualization
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    • v.15 no.1
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    • pp.25-31
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    • 2017
  • This study aims to visualize the Marangoni flow inside a droplet placed on heated hydrophobic surface and to measure its internal velocity field. The experimental result shows that the internal velocity increases with the increase of the plate temperature. In addition, the temperature difference induces the initial flow and drives the Marangoni circulation inside the droplet as soon as the evaporation starts (i.e. the thermal Marangoni flow). The fluorescence particles in the droplet trace two large-scale counter-rotating vortex pairs yielding the downwards flow along the vertical central axis. These vortex pairs gradually become small and move towards the contact line as time goes by, and this Marangoni flow sustains only for a half of the total evaporation time.

Visualization of Gas/liquid Ejector Flow and Void Fraction Measurement using Fiber Optic Probe (기체-액체 이젝터 유동의 가시화와 광섬유 탐침에 의한 기포분율 측정)

  • Choi, Sung Hwan;Ji, Ho Seong;Kim, Kyung Chun
    • Journal of the Korean Society of Visualization
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    • v.11 no.1
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    • pp.34-40
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    • 2013
  • Gas/liquid two-phase ejector is a device without moving parts, in which liquid is used to drive gas of a low-pressure source. In this paper, the hydrodynamic characteristics of a vertical down type two-phase ejector were studied using an air-water loop system. Entrained air flow rates were measured with inlet and outlet pressures of the ejector with varying water flow rate. Homogeneous bubbly flows in the discharge pipe were confirmed by the high speed flow visualization method. Quantitative measurements of void fraction were made using a newly developed fiber optic probe system.

The Dynamic Function Configuration User Interface For CFD Data Visualization Applications (유동해석 데이터 가시화 어플리케이션을 위한 동적 기능 구성 사용자 인터페이스)

  • Hur, Young-Ju;Lee, Joong-Youn;Kim, Min-Ah
    • Proceedings of the Korea Information Processing Society Conference
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    • 2017.11a
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    • pp.1001-1004
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    • 2017
  • 본 논문에서는 유동해석 데이터를 기반으로 하는 가시화 어플리케이션을 위한 동적 기능 구성 사용자 인터페이스를 제안한다. 본 논문에서 제안하는 동적 기능 구성 사용자 인터페이스는 해석 데이터의 메타 데이터 분석 결과를 이용, 데이터 중심의 사용자 인터페이스를 제공함으로써 가시화 관련 기반지식이 없는 유동해석 분야 전문가들이 보다 용이하게 원하는 가시화 결과를 얻을 수 있게 해준다. 제안한 사용자 인터페이스의 사용성을 검증하기 위해 응용 분야 전문가들을 대상으로 사용성 평가를 진행하고 그 결과를 제시한다.

Flow Visualization Using Thin Oil-Film in the Flow Control of Shock Wave/Turbulent Boundary-Layer Interactions (충격파와 경계층 간섭유동 제어에서 오일막을 이용한 유동가시화)

  • Lee Yeol
    • 한국가시화정보학회:학술대회논문집
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    • 2002.11a
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    • pp.117-120
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    • 2002
  • An experimental research has been carried out for flow control of the shock wave/turbulent boundary-layer interaction utilizing aeroelastic mesoflaps. Various shapes and thicknesses of the mesoflap are tested to achieve different deflections of the flap, and ail the results are compared to the solid-wall reference case without flow-control mechanism. Quantitative variation of skin friction has been measured downstream of the interactions using the laser interferometer skin friction meter, and qualitative skin friction distribution has been obtained by observing the interference fringe pattern on the oil-film surface. A strong spanwise variation in the fringe patterns with a narrow region of separation near the centerline is noticed to form behind the shock structure, which phenomenon is presumed partially related to three-dimensional flow structures associated with both the sidewalls and the bottom test surface. The effect of the shape of the cavity is also observed and it is noticed that the shape of the cavity is not negligible.

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