• 제목/요약/키워드: Partition enclosure

검색결과 11건 처리시간 0.016초

격판을 가진 밀폐공간내의 자연대류 열전달에 공간 및 격판의 경사가 미치는 영향 (Effects of Inclination of Enclosure and Partition on Natural Convective Heat Transfer in a Partitioned Enclosure)

  • 정인기;송동주;김점수
    • 설비공학논문집
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    • 제6권3호
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    • pp.302-314
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    • 1994
  • The effects of the inclination of enclosure and partition on natural convective flow and heat transfer were investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was positioned perpendicularly at the mid-height of one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were performed with the variations of the partition length and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). The effects of the inclination angle of enclosure and partition on the heat transfer within an enclosure were also studied. As the results, the increase of the inclination angle of enclosure rapidly raised the heat transfer rate, while the inclination angle for the maximum Nusselt number was retarded with the increase of the partition length and the decrease of the heat transfer rate became larger in proportion to the increase of the partition length. The Nusselt number obtained by the inclination of partition was smaller than that of the inclination of enclosure. However, the difference of the heat transfer rates was considerably decreased at the longer partition lengths and the trends for the variation of the average Nusselt number were more similar with that of the inclination of enclosure. The upward oriented partition increases the convective heat transfer distinctly in contrast to that of the inclination of enclosure as the partition length increases.

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수평격판을 갖는 정사각형 밀폐공간내에서 자연대류 유동 및 열전달 (Natural Convective Flow and Heat Transfer in a Square Enclosure with a Horizontal Partition)

  • 정인기;김점수;송동주
    • 대한기계학회논문집
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    • 제17권9호
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    • pp.2304-2314
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    • 1993
  • Natural convective flow and heat transfer in a two-dimensional square enclosure fitted with a horizontal partition are investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was situated perpendicularly at the one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were carried out with the variations of length, position and thermal conductivity of the partition, and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). As the results, an oscillatory motion of natural convection is resulted in a sudden rise of overall heat transfer, but the increase of length of partition is significantly restrained the increase of Nusselt number. The maximum heat transfer was shown just before the transition of the direction of oscillating flow. An oscillatory motion of flow was perfectly shown the stability with the decrease of the length of partition and Rayleigh number. Also, the heat transfer was raised with the increase of the thermal conductivity in proportion to the increase of the length of partition. The stability and oscillation of flow are affected by the position of partition.

정사각형 밀폐공간내에서 수평격판에 의한 자연대류의 진동현상 (Oscillatory Motion of Natural Convection in a Square Enclosure with a Horizontal Partition)

  • 김점수;정인기;송동주
    • 설비공학논문집
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    • 제5권4호
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    • pp.285-294
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    • 1993
  • An oscillatory motion of natural convection in a two-dimensional square enclosure fitted with a horizontal partition is investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was positioned perpendicularly at the mid-height of one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were carried out with the variations of the partition length and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). As the results, an oscillatory motion of natural convection has perfectly shown the periodicity with the decrease of Rayleigh number, and the stability was reduced to a chaotic state with the increase of Rayleigh number. The period of oscillation gets shorten with the decrease of the partition length and the increase of Rayleigh number. The frequency of oscillation obtained by the variations of stream function is more similar to the experimental results than that of the average Nusselt number. The stability of oscillation grows worse with the increase of Rayleigh number. The transition Rayleigh number for the chaos is gradually decreased with the increase of the partition length.

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제어판이 부착된 수평격판에 의해 분리되는 밀폐공간내의 난류 자연대류 열전달 특성 (Turbulent natural convective heat transfer charateristics in a square enclosure with control plates attached at the horifontal partition)

  • 김점수
    • 설비공학논문집
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    • 제12권2호
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    • pp.150-160
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    • 2000
  • Turbulent natural convective flow and heat transfer in a square enclosure with horizontal partition are investigated numerically. The enclosure is composed of a lower hot and a upper cold horizontal walls and adiabatic vertical walls. Partitions carried with the upward, downward, and both control plates are attached perpendicularly to the one of the vertical insulated walls, respectively. The low Reynolds number $k-\varepsilon$ model is adopted to calculate the turbulent thermal convection. The governing equations are solved by using the finite element method with Galerkin method. The computations have been carried out by varying the length of partition, the position of control plates, and the Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height for water(Pr=4.95). When the control plates are attached at the edge of partition, the stability of oscillating flow grows wrose with the increase of Rayleigh number and the partition length. The heat transfer rate has been reducer than that of no control plate due to the restraint of control plates with the increase of Rayleigh number.

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격판이 존재하는 정사각형 밀폐공간내의 자연대류에 대한 PIV 계측 (PIV Measurement of Natural Convection in a Square Partitioned Enclosure)

  • 김광희;김유곤
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집E
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    • pp.708-713
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    • 2001
  • The paper presented some results of a experimental study of natural convection in partitioned 2D square enclosure. The square enclosure consist of two adiabatic vertical walls and the upper cold and the lower hot walls. A partition is positioned perpendicularly at the center of left vertical insulated wall The PIV mesaurements were performed with the variations of the partition length and inclination of enclosure. The working fluid is water with a Prandtl number of 6.996 at $20^{\circ}C$ temperature. A captured images were calculated by using a Cross-Correlation(Multi-frame/Single-exposure) method.

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격판이 존재하는 경사진 정사각형 밀폐공간 내의 자연대류유동에 관한 실험적 연구 (Experimental Study for Natural Convection Flow in an Inclined Partitioned Square Enclosure)

  • 김광희;김유곤
    • 대한기계학회논문집B
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    • 제26권2호
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    • pp.310-317
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    • 2002
  • In the present study, an experimental study of natural convection in a partitioned 2D square enclosure has been carried out. The square enclosure consist of two adiabatic vertical walls and the upper cold and the lower hot walls. A partition is positioned perpendicularly at the center of the left vortical insulated wall. The PIV measurements were performed with the variations of Rayleigh number, partition length and inclination of the enclosure. The working fluid is water with Prandtl number of 6.996 at 20$\^{C}$. The captured images were analyzed by using a cross-correlation (two-frame/single-exposure) PIV method.

EFFECT OF PARTITION AND SPECIES DIFFUSIVITY ON DOUBLE DIFFUSIVE CONVECTION OF WATER NEAR DENSITY MAXIMUM

  • Sivasankaran, S.;Kandaswamy, P.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제11권1호
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    • pp.71-83
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    • 2007
  • The double diffusive convection of cold water in the vicinity of its density maximum in a rectangular partitioned enclosure of aspect ratio 5 with isothermal side walls and insulated top and bottom is studied numerically. A thin partition is attached to the hot wall. The species diffusivity of the fluid is assumed to vary linearly with concentration. The governing equations are solved by finite difference scheme. The effects of position and height of the partition, variable species diffusivity and enclosure width are analyzed for various hot wall temperatures. It has been found that adding partition on the hot wall reduces the heat transfer. The density inversion of the water has a great influence on the natural convection. When increasing species diffusivity parameter heat and mass transfer rate is decreased.

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수평격판을 갖는 4각형 밀폐공간내에서 자연대류의 진동유동 (Oscillatory Motion of Natural Convective Flow in Partially Divided Square Enclosure)

  • 김점수;정인기;송동주
    • 대한기계학회논문집
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    • 제16권10호
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    • pp.1963-1970
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    • 1992
  • 본 연구에서는 Fig.1에 나타낸 정 등의 모델을 사용하여 공간내의 자연대류 유동을 수치적으로 해석하고 실험결과와 비교하여 수평격판에 의해서 발생하는 진동유 동의 특성을 규명하고자 한다. 본 수치해석에서는 물(Pr=4.95)을 내부유체로 하여 Rayleigh수, 공간의 폭에 대한 격판길이(L/W)및 격판의 열전도율의 변화가 자연대류 진동유동에 미치는 영향을 밝히고, 밀폐공간의 경사에 의해 진동유동이 사라지는 각 도, 즉 천이 경사각도를 찾아 내고자 한다. 이러한 유동특성을 파악하기 위하여 본 연구에서는 지배방정식을 Galerkin method를 사용한 2차원 유한요소법(FEM)으로 수치 해석하였다.

수평격판으로 분리된 정사각형 밀폐공간내의 층류 자연대류 해석 (An investigation of laminar natural convection in a square partitioned enclosure)

  • 김점수;정인기
    • 설비공학논문집
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    • 제9권3호
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    • pp.312-322
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    • 1997
  • The natural convective flow in a two-dimensional square enclosure with horizontal partitions is investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and two identical partitions were positioned perpendicularly at the mid-height of the right and left walls, respectively. The governing equations are solved by using the finite element method with Galerkin method. Calculations are made for different partition lengths, partition conductivites, and Rayleigh numbers based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). An oscillatory motion of the natural convective flow is affected significantly by the variation of the gap width and Rayleigh number. When the gap width is comparatively short, the heat transfer rate is raised with the increase of the thermal conductivity of partitions. However, for sufficiently large gap widths at higher Rayleigh numbers, the average Nusselt numbers of the conductive partitions are smaller than those of the adiabatic partitions.

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파티션의 두께 및 틈새를 고려한 에어컨 캐비닛의 차음 성능 평가 및 음향 삽입 손실 향상에 대한 실험적 분석 (Evaluation for the Capability of the Sound Insulation and Experimental Analysis for the Improvement of the Sound Insertion Loss of the Air Conditioner-cabinet Considering the Thickness and Aperture of the Partition)

  • 한형석;정우승;모진용
    • 한국소음진동공학회논문집
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    • 제18권2호
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    • pp.263-271
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    • 2008
  • Compressor radiated noise is one of the dominant noise for the outdoor unit of the air conditioner. Therefore, air conditioner makers are trying to reduce it continuously. Even though noise absorption and isolation technology are one of the important parts for reducing the noise from the compressor, it is usually treated to the substitute technology when the noise from the compressor is very difficult to reduce by the compressor noise control only. In this paper, we focus on the property of the sound insulation for the cabinet and measure it applying the theory of the sound transmission loss and insertion loss of the simple enclosure. The insertion loss is evaluated by the experiments according to the thickness and the aperture of the partition in the cabinet.