• Title/Summary/Keyword: 무차원 국소 열유속

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Air-side flow and heat transfer for a two-row lanced finned tube heat exchanger (2열 절개형 핀-관 열교환기의 공기측 유동 및 열전달 특성)

  • Bae, Jin-Hyo;Lee, Jae-Heon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.1
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    • pp.79-92
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    • 1998
  • A numerical study has been performed to obtain the air-side flow and heat transfer characteristics for a two-row lanced finned tube heat exchanger with 7 mm tube outer diameter. The increases of dimensionless local heat flux at the leading edge of slit and bottom surface of the fin were noticed. The temperature of air at downstream of the 2nd row of the lanced fin becomes more uniform than that of the plain fin because the mixing of energy increases by the slit and the side-slit. As the inlet velocity increases, the contribution of the 1st row to heat transfer decreases and that of 2nd row increases.

Effect of Circumferential Wall Heat Conduction on Boundary Conditions for Convection Heat Transfer from a Circular Tube in Cross Flow (원관 주위의 대류 열전달에서 경계조건에 대한 원주방향 열전도의 영향)

  • 이상봉;이억수;김시영
    • Journal of Ocean Engineering and Technology
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    • v.15 no.2
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    • pp.39-45
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    • 2001
  • With uniform heat generation from the inner surface of the cylindrical heater placed in a cross flow boundary condition, heat flow that is conducted along the wall of the heater creates a non-isothermal surface temperature and non-uniform heat flux distribution. In the present investigation, the effects of circumferential wall heat conduction on convection heat transfer is investigated for the case of forced convection around horizontal circular tube in cross flow of air. The wall conduction number which can be deduced from the governing energy equation should be used to express the effect of circumferential wall heat conduction. It is demonstrated that the circumferential wall heat conduction influences local Nusselt numbers of one-dimensional and two-dimensional solutions.

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