Penetrative Convection in a Partially Open Enclosure.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899