STUDY OF NATURAL-CONVECTION IN AN ENCLOSURE BOUNDED BY 2 CONCENTRIC CYLINDERS AND 2 DIAMETRIC PLANES

The two-dimensional heat transfer induced by free laminar convection i n an enclosure is numerically investigated in this work. A constant wa ll hear flux is applied on the inner cylinder while the outer is maint ained at an uniform temperature, the others walls being adiabatic. The influence of the modified Grashof number (10(2) less than or equal to Gr less than or equal to 10(6)) and an aspect F-r on convective motio n and heat transfer is examined, A comparison of the heat transfer bet ween different fluids such as air, ammnonia - liquid, and carbon dioxi de-liquid is also displayed. Holographic interferometry is used to vis ualize the temperature field within the enclosure and to confirm the t wo-dimensional behavior of the convective flow. The results show that maximum heat transfer is found for F-r = 1, when the Grashof number is up to 10(3), and the conduction regime is reached for a modified Gras hof number less than 10(3). On the other hand, the average Nusselt num ber increases with the Prandtl number, F-r = 1.