• Title/Summary/Keyword: 감온액정

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A Study on the Visualization of Temperature Field Using Neural Network (신경회로망을 이용한 온도장 가시화에 관한 연구)

  • Lee, C.J.;Bae, D.S.
    • Journal of Power System Engineering
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    • v.16 no.3
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    • pp.37-43
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    • 2012
  • 감온액정을 추적입자로 사용한 PIV(Particle Image Velocimetry)법이 온도장을 정량적으로 가시화하기 위하여 사용되었다. 이 방법은 전체 유동장과 온도장을 동시에 계측할 수 있는 방법이지만, 온도장의 온도는 온도에 따라 변화되는 액정의 색을 정량적 온도 값으로 변환시켜야한다. 따라서 본 연구에서는 감온액정에 의한 온도장의 광학적 정보를 정량적 온도로 변환시키는 신경회로망 보정기법을 개발하여 그 타당성을 검토한 후, 수직온도구배를 가진 액체의 기포에 의한 대류유동에 적용하여 기포에 의한 온도혼합과정을 정량적으로 가시화하고자 한다.

An Experimental Study on Temperature and Velocity Fields of the Turbulent Flows Horizontal Cylindrical Tube by Using Thermo-sensitive Liquid Crystal (수평원통 관에서 감온액정을 이용한 난류유동의 온도 및 속도장에 관한 실험적 연구)

  • 장태현;도덕희
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.7
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    • pp.921-929
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    • 2003
  • An experimental investigation was performed to study the characteristics of turbulent water flow in a horizontal circular tube by using liquid crystal. To determine some characteristics of the turbulent flow, 2D PIV technique is employed for velocity measurement and liquid crystal is used for heat transfer experiments in water. Temperature visualization was made quantitatively by calibrating the color of the liquid crystal versus temperature using various approaches (TLC technique: Thermochromic Liquid Crystal), and a neural-network algorithm was applied to the color-to-temperature calibration. This study shoud the temperature and time-mean velocity distribution for Re = 2,436, 2,500 and 2,724 along longitudinal sections and the results appear to be physically reasonable.

A Study on the Quantitative Visualization of Rayleigh-Bernard Convection Using Thermochromic Liquid Crystal (감온액정을 이용한 Rayleigh-Bernard 대류의 정량적 가시화에 관한 연구)

  • 배대석;김진만;권오봉;이동형;이연원;김남식
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.3
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    • pp.395-404
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    • 2003
  • Quantitative data of the temperature and velocity were obtained simultaneously by using liquid crystal tracer. PIV(Particle Image Velocimety) based on a grey-level cross-correlation method was used for visualizing and analysis of the flow field. The temperature gradient was obtained by applying the color-image processing to a visualized image, and a neural-network a1gorithm was applied to the color-to-temperature calibration. This simultaneous measurement was applied to the Rayleigh-Bernard convection. This paper describes the method, and presents the quantitative visualization of Rayleigh-Bernard convection and the effect of aspect ratio and viscosity. Also the experimental results were compared with the numerical results.

A Study on the Analysis of Temperature Field of Bubbly Flow Using Thermo-sensitive Liquid Crystals (감온액정을 이용한 기포유동의 온도장 해석에 관한 연구)

  • Bae, Dae-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.11
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    • pp.1572-1578
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    • 2003
  • Particle Image Thermometry(PIT) with liquid crystal tracers is used for visualizing and analysis of the bubbly flow in a vertical temperature gradient. Quantitative data of the temperature were obtained by applying the color-image processing to a visualized image, and neural-network was applied to the color-to-temperature calibration. This paper describes the method, and presents the transient mixing temperature patterns of the bubbly flow.

An Experimental Study on Transient Heat Transfer Characteristics of Gas Turbine Cooled Vane by Using Liquid Crystal Thermography (가스터빈 냉각 베인에서 감온액정을 이용한 과도적 열전달 특성에 관한 실험적 연구)

  • Suh Nam-Kyu;Chang Tae-Hyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.1
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    • pp.22-29
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    • 2006
  • Gas turbine engine among Principal internal combustion engines has been mainly applied as an aero and industrial Power plant. In order to increase its thermal efficiency. it has been raised their pressure ratio of compressor and the turbine inlet temperature. To operate above the limit temperature of turbine material, turbine nozzle vanes should be cooled. For this the cooling air is bled from the compressor section of 9as turbine. Meanwhile, to keep high thermal efficiency of 9as turbine, turbine vanes are to be cooled by using small cooling air Therefore, the complex cooling passages are requested to be designed and evaluated the effectiveness of vane cooling by measuring turbine vane temperature. But it is very difficult or impossible for us to measure local turbine temperatures at actual temperature When local heat transfer coefficients are known these can be calculated, therefore this study has been investigated on obtaining these coefficients of turbine vane at room temperature using TLC.

A Study on the Flow Behavior of Magnetic Fluids in a half Circular Pipe (반원관내 자성유체의 자연대류에 관한 연구)

  • Hwang, Sung-Wook;Park, Joung-Woo;Seo, Lee-Soo
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3098-3103
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    • 2007
  • In this paper, natural convection of a magnetic fluids(W-40) in a half circular pipe enclosure are investigated by numerical and experimental method. One side wall is kept at a constant temperature(25$^{\circ}C$), and the opposite side wall is also kept at a constant temperature(20$^{\circ}C$). Under above conditions, various magnitudes of the magnetic fields were applied up. Theoretical study through the governing equation derived by Siliomis is carried out with numerical analysis by the GSMAC Method. And the thermo-sensitive liquid crystal film(R20C5A) is utilized in order to visualize wall-temperature distributions as an experimental method. This study has resulted in the following fact that the natural convection of a magnetic fluids are controlled by the direction and intensity of the magnetic fields.

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A Study on the Flow Analysis for Natural Convection of Magnetic Fluid in a Cubic Cavity (밀폐공간내 자성유체의 유동특성에 관한 연구)

  • Ryu, Shin-Oh;Park, Joung-Woo;Seo, Lee-Soo
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.142-147
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    • 2001
  • Natural convection of a magnetic fluid is different from that of Newtonian fluids because magnetic body force exists in an addition to gravity and buoyancy. In this paper, natural convection of a magnetic fluids(W-40) in a cubic cavity is examined by numerical and experimental method. One side wall was kept at a constant temperature($25^{\circ}C$), and the opposite side wall was also held at a constant but lower temperature($20^{\circ}C$). Under above conditions, various magnitudes of the magnetic fields were applied up. GSMAC scheme is used for a numerical method, and the thermo-sensitive liquid crystal film(R20C5A) is utilized in order to visualize wall-temperature distributions as an experimental method. This study has resulted in the following fact that the natural convection of a magnetic fluids is controlled by the direction and intensity of the magnetic fields.

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Experimental study of natural convection for magnetic fluids in annular pipes (이중원관내 자성유체의 자연대류에 관한 실험적 연구)

  • Park, Joung-Woo;Lee, Jun-Hee;Seo, Lee-Soo
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.191-195
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    • 2001
  • The applications of magnetic fluid can be normally made by 1) using changes of a property of matter caused by applied magnetic field; 2) preserving magnetic fluid at a certain position or in a magnetic fluid keeping the body in a floating condition; 3) controlling the flow of magnetic fluid by means of magnetic field. However, these are usually made by using their methods together. In this study, the natural convection flow of a magnetic fluid in annular pipes is experimentally analyzed. High temperature is kept constantly inside of a circular pipe of experimental model, on the other hand, low temperature is kept constantly outside of it. In experiments, several cases are carried out in order to clarify the fluence of direction and intensity of magnetic fields on the natural convection of magnetic fluid. Therefore magnetic fields are applied in various intensity and up and down directions by permanent magnets.

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An Experimental Study on Laminar Flow Temperature Using Thermo-sensitive Liquid Crystal (감온액정을 이용한 층류유동의 온도장에 관한 실험적 연구)

  • Chang, Tae-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.6 no.4
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    • pp.373-378
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    • 2003
  • An experimental investigation was performed to study the characteristics of laminar water flow in a horizontal circular tube by using liquid crystal. A simultaneous measurement technique has been employed to measure the temperature field in a two-dimensional cross section of fluid flow. This study found the temperature distribution for Re =900~1,500 along longitudinal sections and the results appear to be physically reasonable. To determine some characteristics of the laminar flow, 2D PIV technique is employed for temperature measurement and liquid crystal is used for heat transfer experiments in water. The experimental rig was manufactured from an acryle tube. The test tube diameter of 25mm, and a length of 1200mm. The used algorithm is the gray level cross-correlation method by using Kimura et al. in 1986.

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An Experimental Study on Laminar Flow Velocity by Using Thermo-sensitive Liquid Crystal (감온액정을 이용한 층류유동의 속도장에 관한 실험적 연구)

  • Chang, Tae-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.7 no.1
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    • pp.19-24
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    • 2004
  • An experimental investigation was performed to study the characteristics of laminar water flow in a horizontal circular tube by using liquid crystal. A simultaneous measurement technique has been employed to measure the velocity field in a two-dimensional cross section of fluid flow. This study found the velocity distributions for Re = 1,594 ~ 2,510 along longitudinal sections and the results appear to be physically reasonable. To determine some characteristics of the laminar flow, 2D PIV technique is employed for velocity measurement by using liquid crystal in water. The experimental rig was manufactured from an acryle tube. The test tube diameter of 25mm, and a length of 1200mm. The used algorithm is the gray level cross-correlation method by using Kimura et al. in 1986.

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