COMBINED FORCED AND BUOYANCY-INDUCED CONVECTIVE HEAT TRANSFER IN A PARTIALLY CLOSED VERTICAL CHANNEL

Abstract

This paper reports a numerical study of mixed convection flow over a horizontal surface in a partially closed adiabatic symmetric vertical channel. For low Rayleigh numbers, the forced flow enhances the buoyant convective heat transfer rates. For higher Rayleigh numbers, complex interactions arise between the buoyancy-induced flow and forced convection. The shearing between the buoyancy-dominated wall layer and the forced flow over it induces a stagnation region and a pair of weak recirculating cells in the middle of the channel above the horizontal surface. This effectively reduces heat transfer rates. Nusselt number data are presented for a wide range of Rayleigh and Reynolds numbers. Finally, the effect of the inlet height of forced flow on the transport is discussed.