Natural Convection and Conduction in Porous Wall, Solar Collector Systems Without Vents

Abstract

Steady natural convection heat transfer has been studied in porous wall, solar collector systems. The boundary conditions were: two isothermal walls at different temperatures, two horizontal bounding adiabatic walls, and either uniform or nonuniform heat generating porous layer without vents. The aspect ratio A was from 0.5 to 1.4. The Rayleigh number varied from 103 to 108 . The Darcy number was from 10−8 to 10−2 but the detailed studies were carried out only for 10−4 , an optimum value. The results are presented in terms of thermal parameters (θ, θmax , Nu) as a function of Ra and other nondimensional parameters (A=H/L, B=1/L, F=d/L, kr ). The isotherms and streamlines within the system are also produced. The overall results indicate that geometrical parameters are the most important parameters affecting the system performance.