FREE CONVECTION HEAT TRANSFER IN AN INCLINED ANNULAR POROUS MEDIUM.
Gamal Bedair AbdEl-Aziz;
Abstract
Experimental study was carried out for the steady laminar natural convection of air in an inclined annulus porous medium, with constant heat flux heated inner cylinder and an isothermally cooled outer cylinder. The primary objective of the study is to show the effect of the inclination angle of the annulus and the porosity on the heat transfer characteristics. The geometrical parameters of the annulus are: diameters of
21/45mm, gab width 5=12mm, length L=492mm, and an aspect ratio (length/gab width) A=41. The annulus is filled with spherical beads of diameters d=6.35, 3.97 and 3.11 mm with porosities of 0.45, 0.43 and 0.42 respectively. The operating parameters are: generated heat energy 4:s;Q:s;324W with heat flux 0.123:s;q:s;l1.16kW jm2 , Rayleigh number IO:s;Ra:s;SSO and
inclination angle o::;;e::;;goo.
This study showed that the behavior of free convection heat transfer in an inclined porous annulus is completely different 'from that in a horizontal or vertical one. The inner surface temperature increases with the increase of distance from the bottom of the annulus. For high inclination angles
8 45°, high heat fluxq 2."5kW jm2, input power Q 81W, a drop in the local temperature in the longitudinal direction followed by an increase is observed near •the midsection, indicating the. existence of two cells of flow inside the annulus.
21/45mm, gab width 5=12mm, length L=492mm, and an aspect ratio (length/gab width) A=41. The annulus is filled with spherical beads of diameters d=6.35, 3.97 and 3.11 mm with porosities of 0.45, 0.43 and 0.42 respectively. The operating parameters are: generated heat energy 4:s;Q:s;324W with heat flux 0.123:s;q:s;l1.16kW jm2 , Rayleigh number IO:s;Ra:s;SSO and
inclination angle o::;;e::;;goo.
This study showed that the behavior of free convection heat transfer in an inclined porous annulus is completely different 'from that in a horizontal or vertical one. The inner surface temperature increases with the increase of distance from the bottom of the annulus. For high inclination angles
8 45°, high heat fluxq 2."5kW jm2, input power Q 81W, a drop in the local temperature in the longitudinal direction followed by an increase is observed near •the midsection, indicating the. existence of two cells of flow inside the annulus.
Other data
| Title | FREE CONVECTION HEAT TRANSFER IN AN INCLINED ANNULAR POROUS MEDIUM. | Other Titles | انتقال الحرارة بالحمل الحر فى قطاع مسامى حلقى مائل | Authors | Gamal Bedair AbdEl-Aziz | Issue Date | 1999 |
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