Effects of wall conduction, internal heat sources and an internal baffle on natural convection heat transfer in a rectangular enclosure

This paper presents results of steady-state experiments concerned with natural convection heat transfer of air in a rectangular pool in terms of the Nusselt number (Nu) versus the modified Rayleigh number (Ra′) varying from 109 to 1012. Cartridge heaters were immersed in the working fluid to simulate uniform volumetric heat generation. Two types of boundary conditions were adopted in the test: (I) top cooled, and (II) top and bottom cooled. The other sides were kept insulated. In the case of boundary condition II, the upward heat transfer ratio, Nuup∕(Nuup+Nudn), turned out to be 0.7–0.8 in the range of Ra′ between 1.05×1010 and 3.68×1011.

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FREE CONVECTION HEAT TRANSFER WITH INTERNAL HEAT SOURCES CALCULATIONS AND MEASUREMENTS

10.1615/ihtc5.2950 ◽

1974 ◽

Cited By ~ 35

Author(s):

M. Jahn ◽

H.-H. Reineke

Keyword(s):

Heat Transfer ◽

Free Convection ◽

Convection Heat Transfer ◽

Internal Heat ◽

Heat Sources ◽

Convection Heat ◽

Free Convection Heat ◽

Internal Heat Sources

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Natural Convection From Protruding Heat Sources in a Channel

Heat Transfer: Volume 3 ◽

10.1115/ht2003-47419 ◽

2003 ◽

Cited By ~ 1

Author(s):

Tunc Icoz ◽

Qinghua Wang ◽

Yogesh Jaluria

Keyword(s):

Heat Transfer ◽

Fluid Flow ◽

Natural Convection ◽

Rayleigh Scattering ◽

Convection Heat Transfer ◽

Separation Distance ◽

Natural Convection Heat Transfer ◽

Temperature Profiles ◽

Heat Sources ◽

Convection Heat

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.

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