• 제목/요약/키워드: 휜이 부착된 관

검색결과 4건 처리시간 0.017초

내부휜이 부착된 원형관 열교환기의 열/유동 해석 및 최적설계 (Flow/Heat Transfer Analysis and Shape Optimization of a Heat Exchanger with Internally Finned Tube)

  • 이주희;이상환;임효재;박경우
    • 대한기계학회논문집B
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    • 제29권4호
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    • pp.460-468
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    • 2005
  • Analyses of flow and heat transfer characteristics and shape optimization of internally finned circular tubes have been performed for three-dimensional periodically fully developed turbulent flow and heat transfer. CFD and mathematical optimization are coupled in order to optimize the shape of heat exchanger. The design variables such as fin widths $(d_{1},\;d_{2})$ and fin height (h) are numerically optimized by minimizing the pressure loss and maximizing the heat transfer rate for limiting conditions of $d_{1}=0.2\~1.5\;mm,\;d_{2}=0.2\~1.5\;mm,$ and $h=0.2\~1.5mm$. Due to the periodic boundary conditions along main flow direction, the three layers of meshes are considered. The flow and thermal fields are predicted using the finite volume method and the optimization is carried out by means of the sequential quadratic programming (SQP) method which is widely used in the constrained nonlinear optimization problem.

휜이 부착된 수직(垂直) 냉각관(冷却管)에서의 열전달(熱傳達)에 관(關)한 실험적(實驗的)인 연구(硏究) (An experimental study on heat transfer of finned vertical cooling tube)

  • 송하진;이채문;임장순
    • 태양에너지
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    • 제4권2호
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    • pp.43-49
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    • 1984
  • Experiments were performed to study freezing on a finned vertical tube when either conduction in the solid or natural convection in a liquid controls the heat transfer. Conduction is the controlling mode when the liquid is at its fusion temperature, whereas natural convection controls when the liquid temperature is above the fusion value. The liquid was housed in a cylinderical containment vessel whose surface was maintained at a uniform, time-invariment temperature during a data run, and the freezing occurred on a finned vertical tube positioned along the axis of the vessel. The phase change medium was n-octacosan, a paraffin which freezes at about $61^{\circ}C$. For conduction-controlled freezing, the enhancement of the frozen mass due to finning is greatest when the frozen layer is thin and decrease as the layer grows thicker. The degree of enhancement is generally less than the surface area ratio of the finned and unfinned tube.

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내관에 휜을 부착한 진공관형 집열기의 열성능 해석 (Thermal Performance Analysis of Glass Evacuated Solar Collector with a Finned Tube)

  • 김용;서태범;강용혁
    • 한국태양에너지학회 논문집
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    • 제24권1호
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    • pp.39-45
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    • 2004
  • The thermal performance of glass evacuated tube solar collectors with finned tubes is numerically modelled with code and investigated to see the effect of toe inner tube diameter and incidence angle. The solar collector consists of a two-layered glass tube and an inner tube. Finned tubes are used as the inner tube of the collector in order to improve the performance of the solar collector. Two strip-type fins are attached on the opposite sides of the inner tube surface. The fin is wide enough to be tightly fatted inside the glass tube. The results show that if the incidence angle is small, the effect of the tube diameters is not significant on the thermal performance and the outlet air temperature. If the incidence angle is large, however, the outlet air temperature and the performance increases as the inner tube diameter increases.

환형휜이 부착된 두 개의 원형관 배열에 대한 강제대류 열전달 (Forced Convection Heat Transfer for Two Circular Tube Arrays with Annular Fins)

  • 김승일;박상희
    • 한국산업융합학회 논문집
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    • 제23권6_2호
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    • pp.1093-1101
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    • 2020
  • This study was carried out numerically to investigate the air flow and thermal performance around single and parallel fin-tube heat exchangers and the cooling performance of the fluid inside the heat exchangers. In this study, the air velocity(1~7m/s), the pitch of fin(4, 6.1, 8, 11.3, 18.3, 44mm) and the diameter of fin(31, 33, 35, 37, 39mm) were varied. The flow rate of the water at the fin-tube heat exchanger inlet is 89cc/min and the water temperature is 353K. The air temperature at the upstream region of the heat exchanger is 300K. flow rate of the water at the fin-tube heat exchanger inlet is 80cc/min and the water temperature is 353K. It was found that the air pressure drop around single and parallel fin-tube heat exchangers was highly dependent on the air velocity and the fin pitch, but was independent of the fin diameter. Also, it was shown that pressure drop increased more the parallel arrangements than in single heat exchanger. The temperature difference of water at the inlet and outlet of the heat exchanger depended on the air velocity, the fin pitch and the fin diameter, and it was found that the parallel arrangement method further reduced the temperature of water. It was shown that the Nusselt number increased as the Reynolds number and the fin pitch increased, and decreased as the fin diameter increased.