UNSTEADY NON-DARCY REACTION-DRIVEN FLOW FROM AN ANISOTROPIC CYLINDER IN POROUS-MEDIA

This paper reports a theoretical study of thermal convection in a flui d-saturated porous medium generated by a surface reaction. The convect ive phenomena driven by temperature gradients, via heat release from a n nth-order irreversible reaction, are modeled by the Brinkman-Forschh eimer equation including the Boussinesq-Oberbeck approximations togeth er with the energy and species equations. Solutions are obtained by a Fourier spectral element method in conjunction with a semi-implicit me thod combining the second-order Adams-Bashforth and first-order backwa rd Euler schemes for advancing the solution in time. Numerical results indicate a strong influence of natural convection on the physicochemi cal process. Effects due to non-Darcy flow are significant for Rayleig h number on the order of 10(6) and that symmetry about theta = pi pers ists even for anisotropic materials unless the off-diagonal entry of t he thermal conductivity tensor is nonzero. Copyright (C) 1996 Elsevier Science Ltd