Effect of Prandtl Number on Natural Convection in Tilted Square Enclosure with Inner Circular Cylinder

Abstract

A numerical analysis of the effect of the Prandtl number on the natural convection in a cold outer tilted square enclosure with an inner hot circular cylinder is presented. Several Prandtl numbers (Pr=0.1, 0.7, 7) are considered, with different angles(0°, 15°, 30°, 45°) for the enclosure and Rayleigh numbers (Ra=10 3 , 10 4 ,10 5). The effect of the Prandtl number on the natural convection is analyzed using isotherms and streamline and surface-averaged Nusselt numbers. The flow and heat transfer characteristics are found to be dependent on the time for Ra=10 5 and Pr=0.1 at angles of 0° and 45°. However, in the other cases, the flow and heat transfer characteristics are independent of the time.The surfaceaveraged Nusselt number increases with an increase in the Prandtl number. As the Prandtl number increases, the Nusselt number becomes larger regardless of the angle for Ra=10 5. In particular, the Nusselt number steeply increases when the angle is 45° for Ra=10 5 and Pr=0.1.