Natural convection heat transfer characteristics of flat plate enclosures

Journal Article · Thu Feb 01 04:00:00 EST 1979 · J. Heat Transfer; (United States)

DOI:https://doi.org/10.1115/1.3450901· OSTI ID:6149804

Randall, K R; Mitchell, J W; El-Wakil, M M

Heat transfer by natural convection in rectangular enclosures has been experimentally studied using interferometric techniques. The effects of Grashof number, tilt angle, and aspect ratio on both the local and average heat transfer coefficients have been determined. The Grashof number range tested was 4 x 10/sup 3/ to 3.1 x 10/sup 5/, and the aspect ratio (ratio of enclosure length to plate spacing) varied between 9 and 36. The angles of tilt of the enclosure with respect to the horizontal were 45, 60, 75 and 90 deg. Correlations are developed for both local and average Nusselt number over the range of test variables. The effect of tilt angle is found to reduce the average heat transfer by about 18 percent from the value of 45 deg to that at 90 deg. No significant effect of aspect ratio over the range tested was found. A method for characterizing the flow regimes that is based on heat transfer mechanisms is proposed.

• Research Organization: Mechanical and Nuclear Engineering Departments, University of Wisconsin, Madison, Wisconsin.
• OSTI ID: 6149804
• Journal Information: J. Heat Transfer; (United States), Journal Name: J. Heat Transfer; (United States) Vol. 101:1; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000* -- Solar Collectors & Concentrators
ASPECT RATIO
BOUNDARY LAYERS
CONVECTION
CORRELATIONS
ENERGY TRANSFER
FLAT PLATE COLLECTORS
GRASHOF NUMBER
HEAT TRANSFER
INTERFEROMETRY
LAYERS
NATURAL CONVECTION
NUSSELT NUMBER
SOLAR COLLECTORS