Non-Darcy effects on conjugate double-diffusive natural convection in a variable porous layer sandwiched by finite thickness walls

Steady conjugate double-diffusive natural convective heat and mass transfer in a two-dimensional variable porosity layer sandwiched between two walls has been studied numerically. The Forchheimer-Brinkman-extended Darcy model has been used to solve the governing equations in the saturated porous region. The flow is driven by a combined buoyancy effect due to both temperature and concentration variations. An exponential variation of the porosity near the hot wall is considered. The vertical walls are impermeable and subjected to a horizontal gradient of both temperature and concentration while the horizontal walls are adiabatic. A finite volume approach has been used to solve the dimensionless governing equations and the pressure velocity coupling is treated with the SIMPLE algorithm. The model has been validated with available experimental, analytical/computational studies. (C) 2011 Elsevier Ltd. All rights reserved.