Mixed convection-radiation interaction in a vertical porous channel: Entropy generation

The present work examines analytically the effects of radiation heat transfer on magnetohydrodynamic mixed convection through a vertical channel packed with fluid saturated porous substances. First and Second Laws of thermodynamics are applied to analyze the problem. Special attention is given to entropy generation characteristics and their dependency on the various dimensionless parameters, i.e., Hartmann number (Ha), Plank number (Pl), Richardson number (Ri), group parameter (Br/II), etc. A steady-laminar flow of an incompressible-viscous fluid is assumed flowing through the channel with negligible inertia effect. The fluid is further considered as an optically thin gas and electrically conducting. Governing equations in Cartesian coordinates are solved analytically after reasonable simplifications. Expressions for velocity, temperature, local, and average entropy generation rates are analytically derived and presented graphically. (C) 2003 Elsevier Ltd. All rights reserved.