A NUMERICAL STUDY OF NATURAL CONVECTIVE HEAT TRANSFER FROM TWO-SIDED CIRCULAR AND SQUARE HEATED HORIZONTAL ISOTHERMAL PLATES HAVING A FINITE THICKNESS
Several numerical and experimental studies of natural convective heat transfer from two-sided heated horizontal
plates are available. In the numerical studies it has usually been assumed that the plate is thin, effectively having
no thickness, whereas plates of finite thickness have been used in the experimental studies. To determine
whether the plate thickness has a significant influence on the heat transfer rates from the upper and lower
surfaces of the plate, results have here been numerically obtained for circular and square plates having various
thicknesses. The upper and lower surfaces of the plate have been assumed to be isothermal and at the same
temperature. Both the case where the vertical side edges of the plates are isothermal and at the same temperature
as the upper and lower plate surfaces and the case where these side edges are adiabatic have been considered.
The flow has been assumed to be steady and the Boussinesq approach has been adopted. Conditions under which
laminar, transitional, and turbulent flows exist have been considered, the standard k-epsilon turbulence model
being used. The solution has been obtained using ANSYS FLUENT©. Only the case where the heat transfer
from the plate is to air has been considered. Variations of the Nusselt number with Rayleigh number for various
dimensionless plate thicknesses for the two edge conditions considered have been obtained for circular and
square plates. The results indicate that the dimensionless plate thickness has only a modest effect on the heat
transfer rates from the plate surfaces.