A numerical study of buoyancy-induced forced convection on an isolated vertical plate

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:509292

Anderson, A M ^[1]

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1. Union Coll., Schenectady, NY (United States). Dept. of Mechanical Engineering

This paper presents the results of a numerical study of buoyancy-induced forced convection flow on an isolated vertical plate. Buoyancy-induced forced convection occurs when global buoyancy mechanisms are strong enough to be unaffected by local perturbations in wall temperature or heat flux. Under these conditions, the flow field behaves as if it were in forced convection. Ortega and Moffat (1986) showed that buoyancy-induced forced convection exists in a channel flow whenever the ratio of the adiabatic Grashof number to the induced flow Reynolds number squared, Gr{sub ad}/Re{sup 2}, is less than about 0.3. This local phenomena is obscured when one characterizes the flow with global parameters such as the temperature rise above the ambient or inlet temperature. Local heat transfer descriptors, which use the temperature rise above the adiabatic temperature, allow one to separate out the effects of local mechanisms and show that buoyancy-induced forced convection exists. A scaling method is presented to calculate an induced flow Reynolds number and apply the Gr{sub ad}/Re{sup 2} criteria to free convection on an isolated plate. Two fluids (air and water) are examined and the results show that buoyancy-induced forced convection exists on an isolated plate when Gr{sub ad}/Re{sup 2} is less than 1.

• OSTI ID: 509292
• Report Number(s): CONF-950828--; ISBN 0-7918-1702-4
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COOLING
ELECTRONIC EQUIPMENT
FORCED CONVECTION
NATURAL CONVECTION
NUMERICAL ANALYSIS
TEMPERATURE CONTROL
THEORETICAL DATA