COMBINED FORCED-CONVECTION AND CORRELATED-RADIATION HEAT-TRANSFER IN CYCLINDRICAL PACKED-BEDS

The heat transfer characteristics of a fully developed forced convecti on flow in a cylindrical packed column at high temperatures are examin ed. The effects of non-Darcy and variable porosity are considered in t he momentum equation, while the effects of radial thermal dispersion, variable effective thermal conductivity, and thermal radiation are tak en into account in the energy equation. A new lateral mixing function is introduced to represent radial thermal dispersion coefficient. Radi ative transfer in the packed bed is analyzed by utilizing the P1 appro ximation and the correlated-radiative properties of packed spheres. Af ter confirming the adequacy of the proposed heat transfer model, the e ffects of several system parameters on temperature profiles and heat t ransfer characteristics in cylindrical packed beds are examined in som e detail.