Non-Darcy mixed convection along nonisothermal vertical surfaces in porous media

Abstract

An analysis is performed for mixed convective flow through a fluid-saturated porous medium adjacent to a vertical surface with the heating condition of power-law variation in the wall temperature. The entire mixed convection regime is covered by the single parameter χ = [1+( Ra x/ Pe x) 0.5] −1 from the pure forced convection limit ( χ = 1) to the pure free convection limit ( χ = 0). In modeling the flow through porous media, non-Darcy effects such as high-flow-rate inertia forces, no-slip boundary condition, near-wall porosity variation and thermal dispersion are taken into consideration. Because of the porosity variation in the near wall region, the stagnant thermal conductivity also varies accordingly. The aims of the present work are to examine the effects of non-Darcian flow phenomena on mixed convective transport and to demonstrate the variation in heat transfer predictions based on different flow models. A finite difference scheme was used to solve the transformed system of equations. Numerical results show that non Darcian and thermal dispersion effects have significant influences on velocity profiles, temperature profiles and heat transfer rates from the vertical surface.