Natural convection from a horizontal cylinder placed in a square enclosure: CFD simulations.

Natural convection from a horizontal cylinder placed in a square enclosure is numerically investigated using two different fluids as a heat transfer medium. Water and air are used as two different heat transfer mediums. The diameter and length of the cylinder are 50 mm and 500 mm respectively. The cylinder is placed in a close square enclosure of 300 mm x 300 mm. The range of operating conditions covered different surface temperature from 303 K to 414 K. Two-dimensional Computational Fluid Dynamic (CFD) approach is used to predict the natural convection when water and air are the heat transfer mediums. The Nusselt number is estimated and compared with the experimental result which is obtained from previous study with maximum absolute percentage error of 13%. The results show that the surface temperature has a direct and significant effect on the Nusselt number when the cylinder is surrounded by air as a medium for the heat transfer with maximum velocity varied from 0.007 m/s to 0.11 m/s. Conduction heat transfer mode is the dominant mod when the cylinder is surrounded by water with maximum velocity of 0.3 m/s. at surface temperature of 350 K. [ABSTRACT FROM AUTHOR]