ANALYSIS OF NATURAL-CONVECTION IN VERTICALLY-VENTED ENCLOSURES

Natural convection in vertically-vented enclosures is investigated theoretically. A vertically-vented enclosure is one in which the buoyancy-driven flow and heat transfer are restricted by vents in the top and bottom bounding walls of the enclosure. The governing conservation equations are solved numerically using a control volume-based finite difference technique with the appropriate pressure boundary conditions at the inlet and exit vents. The results reveal strongly non-uniform local heat transfer along the isothermal wall as a result of the blockage at the inlet. A local maximum and minimum in heat transfer occur in the lower half of the enclosure. The predictions for the flow field reveal that these heat transfer extrema are attributed to a recirculation zone near the inlet gap and primary flow attachment along the heated wall. The results show asymptotic behavior to the classical vertical parallel plate result in the limit as the vent gap approaches the enclosure width.