The aspect ratio effect on natural convection in an enclosure with protruding heat sources

Journal Article · Thu Oct 31 23:00:00 EST 1991 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2911217· OSTI ID:7206906

Keyhani, M; Chen, L; Pitts, D R ^[1]

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1. Univ. of Tennessee, Knoxville (United States)

The aspect ratio effect on natural convection heat transfer in a rectangular enclosure with protruding heat sources has been experimentally investigated. Five protruding heaters were mounted with uniform vertical spacing on one vertical wall. The vertical wall opposite to the wall on which heated sections were mounted was movable so that the enclosure width could be adjusted to the desired values. The top surface of the test enclosure was an isothermal heat sink. All other surfaces except the two end vertical surfaces were insulated. The five heaters were identical with each having horizontal protuberance of L{sub 3} = 9 mm and vertical height of L{sub 1} = 15 mm. The vertical spacing between the heaters was L{sub 2} = 15 mm. The enclosure width was varied in experiments from W = 13.5 mm to 45 mm. The experiments were conducted for six values of cavity width resulting in variations in the cavity height-to-width ratios (aspect ratios) and cavity width-to-protruding heater height ratios of 3.67 to 12.22 and 1.5 to 5.0, respectively. Ethylene glycol was used as the convective medium. Flow visualization pictures and heat transfer data indicate that the starting point of core flow directly affects the local heat transfer coefficient of the bottom heater, while the secondary flow cell between the top heated section and the top sink surface influences the heat transfer coefficient of the top heater. The correlation of local Nusselt number versus local modified Rayleigh number is independent of the number of heaters in the vertical array, cavity width-to-heater protrusion height ratio, W/L{sub 3}, and vertical height location of the heaters.

• OSTI ID: 7206906
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 113:4; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
ALCOHOLS
ASPECT RATIO
BENCH-SCALE EXPERIMENTS
CAVITIES
CONVECTION
ENERGY TRANSFER
FLOW VISUALIZATION
GLYCOLS
HEAT TRANSFER
HYDROXY COMPOUNDS
INSTABILITY
MASS TRANSFER
NATURAL CONVECTION
NUSSELT NUMBER
ORGANIC COMPOUNDS
RAYLEIGH-TAYLOR INSTABILITY