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Penetrative Convection in a Partially Open Enclosure.


pdf icon Penetrative Convection in a Partially Open Enclosure. (617 K)
Abib, A. H.; Jaluria, Y.

American Society of Mechanical Engineers (ASME). Natural Convection in Enclosures. HTD-Vol. 192. 1992, Am. Soc. of Mechanical Engineers, New York, NY, 73-81 pp, 1992.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Keywords:

enclosures; convection; heat sources; formulations; equations; stratification; flow fields; temperature; velocity distribution; penetration; heat transfer

Abstract:

The penetrative convection induced by a localized heat source at the bottom of a partially open enclosure, while the background ambient medium is stably and thermally stratified, is considered. A rectangular cavity with a partially open side is assumed to be adjacent to a long corridor which is stably stratified. The stable thermal stratification that is of interest is a two-layered one or a linear temperature stratification. A control-volume finite-difference method, in stream function and vcorticity formulation, is employed for the solution. The influence of the stratification parameter is examined in the laminar flow regime by considering a range of stratification levels. Heat transfer results, mass outflow rate, penetration distance, velocity and temperature distributions are presented to quantify the penetrative convection. It is found that, for a step ambient temperature profie, the convective motion occurring in the lower unstable layer penetrates significantly into the stable upper layer only for a weak stratification. Small penetration occurs at large stratification levels. The flow field reveals a multi-cellular pattern. Furthermore, it is observed that the penetrative motion occurs in the form of nearly horizontal motion in the lowest part of the stable upper-layer. The thermal field is studied in detail. Other important details on the penetrative transport are brought out.