EXPERIMENTAL AND NUMERICAL STUDY OF NATURAL CONVECTION BETWEEN TILTED WALLS WITH ATTACHED FINS

Abstract

The free convection between two tilted adiabatic plates with centered heated horizontal
cylinder with attached plate fin was investigated experimentally and numerically. The
experimental rig constructed from vertical adiabatic was filled with air plates with aspect
ratio of (A= 12) tilted by angles of (15o, 30o, 45o, 60o, 75o, and 90o). A horizontal heated
cylinder with diameter of (16 cm) subjected under constant heat flux of (100, 500, 700, and
1000 W/m2), the Rayleigh number ranging from (3.5 ×107 to 4.5 ×109). At the bottom of the
rig left an opining with distance of (2, 4, 6, and 8 cm) but the upper left open to the
atmosphere. The tested cases was of (without fin, smooth, triangular, square, and semi-circle
fin) was attached to the right wall of the cavity. The numerical solution of the case was
performed by solving the governing equations by ANSYS-FLUENT 14.0 package that
dependent upon the finite volume method. The experimental results show that the Nusselt
number increases with increasing Rayleigh number, decreasing the inclination angle,
increasing heat flux and with increasing the bottom opining distance. Basically, the results
showed that the using fins with any geometry will lead to increase the heat transfer rate. The
optimum increasing in the Nusselt number was found by using triangular plat fin. Finally,
the experimental data was compared with a numerical calculation and found that there is a
good agreement in the same conditions.