Study of Natural Convection in an Enclosure Bounded by Two Concentric Cylinders and Two Diametric Planes

The two-dimensional heat transfer induced by free laminar convection in an enclosure is numerically investigated in this work. A constant wall heat flux is applied on the inner cylinder while the outer is maintained at an uniform temperature, the others walls being adiabatic. The influence of the modified Grashof number (102 ≤ Gr ≤ 106) and an aspect Fr on convective motion and heat transfer is examined. A comparison of the heat transfer between different fluids such as air, ammonia–liquid, and carbon dioxide–liquid is also displayed. Holographic interferometry is used to visualize the temperature field within the enclosure and to confirm the two-dimensional behavior of the convective flow. The results show that maximum heat transfer is found for Fr = 1, when the Grashof number is up to 103, and the conduction regime is reached for a modified Grashof number less than 103. On the other hand, the average Nusselt number increases with the Prandtl number, Fr = 1.