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ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

NON-DARCIAN EFFECTS ON MIXED CONVECTION IN A VERTICAL POROUS ANNULUS

Get access (open in a dialog) DOI: 10.1615/IHTC9.3580
pages 271-276

Abstract

A numerical study of combined free and forced convection in a vertical porous annulus has been performed by using Darcy-Brinkman-Forchheimer equation of motion. Both aiding and opposing flows have been analyzed. A noticeable decrease of the Nusselt number is observed when either the porosity is greater than 0.5, or the dimensionless particle diameter is greater than 0.2. It is also found that while the inertia term has negligible effect on the Nusselt number, the viscous term significantly changes the flow and temperature fields near the boundary and in highly porous media. For aiding flows, the reduction of Nusselt number becomes pronounced as either the Rayleigh number or the Peclet number increases. For opposing flows, however, the influence of both terms is not simple because of the interaction between buoyancy-induced upflow and the external downflow. In a certain range of Peclet number, increases of Nusselt number are observed due to inertial and viscous effects.