Natural convection in a circular enclosure with an internal plate: Effect of inclination and eccentricity

A numerical study of natural convection in an enclosure containing an eccentrically positioned inclined flat plate is performed, and the impact of eccentricity and inclination angle on flow and heat transfer are analyzed using a finite-difference code. The effect of eccentricity on the convection mechanism in the large and small spaces separated by the plate is explored, as well as the way in which the deviation between the directions of the plate and the buoyancy force determines the fluid motion. It is found that the total heat transfer exhibits a dramatic increase as the normalized eccentricity reaches e/D = 0.3, namely, by 21.2%, 13.4%, and 20.5% at α = 0°, 90°, and 180°, respectively, compared with the e/D = 0.2 case, owing to the enhanced heat transfer by conduction, which dominates the local flow and heat transfer in the small region between the plate and the enclosure. When the plate is inclined, primary, secondary, and tertiary vortices are generated in the two halves of the enclosure, and the intensity of the vortices increases as they approach the horizontal centerline. Analysis of the local heat transfer demonstrates that the maximum local heat transfer rate occurs either at the top of the enclosure owing to natural convection or at the position close to the end of the plate, where conduction dominates.