Laminar Free Convection In Horizontal Annulus Filled With Glass Beads And With Annular Fins On The Inner Cylinder

An experimental and numerical study has been carried out to investigate the heat transfer by natural convection radiation in a two dimensional annulus enclosure filled with porous media (glass beads) between horizontal concentric cylinders. The outer cylinders are of (100, 82 and70mm) outside diameters inner cylinder 27 mm diameter (or without) annular fins attached it. Under steady state condition; surface is maintained at high temperature applying uniform flux low inside freezer. experiments were for an glass beads range modified Rayleigh number (4.9 ≤ Ra≤ 69), parameter (0<Rd<10), fin length (Hf=3, 7 11mm), radius ratios (Rr=(r1/r2) =0.1405,0.2045, 0.293 0.3649 ), (n=0, 12, 23 45). Finite difference method Boussinesq's approximation used solve continuity, energy momentum equations. solution capable calculating streamline, field, velocity local average Nusselt number. A computer program Mat lab built carry solution. was done Ra 300). Results show that nearly constant less than 100 increased increase number.Nusselt hardly affected size insignificant Rd 100. Decreasing Rr cause clearly increasing or decrease transfer.