This work is focused on the numerical study of steady, laminar natural convection heat transfer in square enclosure with perfectly conducting thin fins. The fins are attached to both vertical surfaces, the two vertical surfaces are at different temperatures while the other two horizontal surfaces are insulated. In the formulation of governing differential equations, mass, momentum and energy equations are applied to the enclosure. To solve the governing differential equations a finite difference method is used. Three cases were studied in this work depending on the number of fins attached to vertical surface, (i) single fin (ii) two fins and (iii) three fins. The results presented for various Rayleigh number and dimensionless fins length ( in the range of 0.15, 0.25, 0.35, 0.45), in a form of streamlines, isotherm lines, as well as Nusselt number. It was observed that the increasing in Rayleigh number resulting in increase inNusselt number and in the temperature gradient. Due to increasing in the in the dimensionless length and number of fins, it was observed that a decrease in temperature gradient and in the Nusselt number were occurred.
Key words : natural convection, enclosure, fins, heat transfer.