NATURAL CONVECTION IN HIGH ASPECT RATIO THREE-DIMENSIONAL ENCLOSURES WITH UNIFORM HEAT FLUX ON THE HEATED WALL

Abstract

In this work, the laminar natural convection in high aspect ratio three-dimensional
enclosures has been numerically studied. The enclosures studied here were heated with
uniform heat flux on a vertical wall and cooled at constant temperature on the opposite
wall. The remaining walls were considered adiabatic. Fluid properties were assumed
constant except for the density change with temperature on the buoyancy term. The
governing equations were solved using the finite volumes method and the dimensionless
form of these equations has the Prandtl number and the modified Rayleigh number as
parameters. The influences of the Rayleigh number and of the cavity aspect ratio on the
Nusselt number, for a Prandtl number of 0.7, were analyzed. Results were obtained for
values of the modified Rayleigh number up to 106 and for aspect ratios ranging from 1 to
20. The results were compared with two-dimensional results available in the literature and
the variation of the average Nusselt number with the parameters studied were discussed.