Buoyancy-induced heat transfer in a vertical enclosure with offset partial vertical dividers

Abstract

A numerical study has been made of buoyancy-induced flow in a square, externally heated vertical enclosure with two offset baffles or vertical dividers, in order to investigate the effect of baffle height on the flow and heat transfer characteristics. Air is taken to be the working fluid, and the horizontal end walls are assumed to be perfectly conducting. Two baffle positions are considered: in one, the upper baffle is offset toward the hot wall, and the lower baffle toward the cold wall (position A): in the other, the upper baffle is offset toward the cold wall, and the lower baffle toward the hot wall (position B). The effect of baffle conductivity and height on the thermal stratification and heat transfer is investigated. Both factors are found to play an important role, with lower heat transfer at higher baffle conductivities and baffle heights. The nature of thermal stratification between the baffles and in the baffle—near wall region controls the corresponding flow behavior. In position B, strong vertical stratification between the baffles inhibits the crossflow, whereas in position A stratification and correspondingly reduced flow penetration into the baffle—near wall region is noted. These differing flow patterns have important ramifications on the heat transfer.