| This dissertation studies analytically the conjugate mixed-convection conduction heat transfer in porous media. Solutions for mixed convection flows about vertical plate and cylindrical fins embedded in a porous medium have been obtained by including the effects of interactions between the conduction in the solid boundaries (fins) and the convection in the boundary layer. It has been found that the governing parameters are the Prandtl number Pr, buoyancy force parameter (OMEGA), convection conduction parameter Ncc, and the surface curvature parameter (lamda). Extensive results for heat transfer characteristics are presented graphically and in tabular forms for the following ranges of parameters: 0.05 (LESSTHEQ) Pr (LESSTHEQ) 7.5, 0.0 (LESSTHEQ) (OMEGA) (LESSTHEQ) 20.0, 0.0 (LESSTHEQ) Ncc (LESSTHEQ) 2.0 and 0.5 (LESSTHEQ) (lamda) (LESSTHEQ) 5.0. Many results were found to have trends similar to those for classical fluids. In particular, the local heat transfer coefficients for mixed convection flows were found not to decrease monotonically as usual, but instead, the coefficients decreased first, attained a minimum value and then increased with increasing streamwise distance. This behavior is attributable to an enhanced buoyancy force resulting from an increase in the wall-to-fluid temperature difference along the streamwise direction. The total heat transfer rates were found to decrease with increasing Ncc and (lamda).;A computational procedure based on the local nonsimilarity method has been established. The correctness of the numerical procedure was confirmed by verifying some special cases found in the literature. Throughout this study the porous medium was modeled by the use of the Darcy's law. A more generalized model was proposed for further studies. |
