Natural Convection Heat Transfer of a Rectangular Block within a Vertical Enclosure

A numerical solution of the natural convection heat transfer between two cold and hot isolated vertical plates is presented for different horizontal and vertical location ratios of an enclosure. Results show that: a) flow configurations of cold and hot plates are different; b) the increase of vertical location ratio, toward that corresponding to the enclosure middle value, is considerably diminishing the temperature differences between heating and cooling conditions; c) the effect of vertical location ratio variation is more prominent on heat transfer for cold and hot plates than that of the horizontal location ratio variation; d) the average Nusselt number, obtained from the hot isolated plate, is 20–39% larger than that of the cold plate under the same conditions when the isolated plate varies horizontally; e) for a narrow distance between the inner plate and the bounding wall, the inner plate Nusselt number is enhanced, but aside from this, the plate average Nusselt number is insensitive to the plate position; and f) different trends are found to affect heat transfer for cold and hot plates when the isolated plate varies vertically. The optimal vertical location can be found at specific Rayleigh number for the hot plate and cold plate.