An experimental study of natural convection in a vertical cavity with discrete heat sources

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.3250537· OSTI ID:5483694

Keyhani, M; Cox, R ^[1]; Prasad, V ^[2]

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1. Univ. of Tennessee, Knoxville (USA)
2. Columbia Univ., New York, NY (USA)

Natural convection heat transfer in a tall vertical cavity (aspect ratio = 16.5), with one isothermal vertical cold wall, and eleven alternately unheated and flush-heated sections of equal height on the opposing vertical wall, is experimentally investigated. The flow visualization pictures for the ethylene glycol-filled cavity reveal a flow pattern consisting of primary, secondary, and tertiary flows. The heat transfer data and the flow visualization photographs indicate that the stratification is the primary factor influencing the temperature of the heated sections. This behavior persists for all the runs where the secondary flow cells cover a large vertical extend of the cavity. Based on the analysis of the photographs it is suggested that the turbulent flow should be expected when the local modified Rayleigh number is in the range of 9.3 {times} 10 {sup 11} to 1.9 {times} 10{sup 12}. It is found that discrete flush-mounted heating in the enclosure results in local Nusselt numbers that are nearly the same as those reported for a wide flush-mounted heater on a vertical plate. This is believed to be due to the fact that the present problems in inherently unstable, and the smallest temperature difference between a heated section and the cold wall results in the onset of convection motion.

• OSTI ID: 5483694
• Journal Information: Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 110:3; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
ALCOHOLS
CAVITIES
CONVECTION
COOLING
DATA
ELECTRONIC EQUIPMENT
ENERGY TRANSFER
EQUIPMENT
FLOW VISUALIZATION
FLUID FLOW
GLYCOLS
HEAT TRANSFER
HYDROXY COMPOUNDS
INFORMATION
INSTABILITY
MASS TRANSFER
NATURAL CONVECTION
NUSSELT NUMBER
ORGANIC COMPOUNDS
ORIENTATION
RAYLEIGH-TAYLOR INSTABILITY
STRATIFICATION
TURBULENT FLOW