NATURAL CONVECTION IN A CAVITY FILLED WITH POROUS MEDIUM WITH PARTIALLY THERMAL ACTIVE SIDEWALLS UNDER LOCAL THERMAL NONEQUILIBRIUM CONDITIONS

Steady non-Darcian natural convection in a square cavity filled with a heat-generating porous medium is studied numerically by adopting the local thermal nonequilibrium model. All of the walls of the enclosure are adiabatic except the left wall, which is set as the partially active thermal wall. Six different cooling zones are considered along the left vertical wall, and a two-equation model is used in consideration of the microscopic heat transfer between the solid and fluid phases. It is found that the cooling of a single wall can generate unsymmetrical distribution of streamlines, and isotherms of fluid phase in porous enclosures when Rayleigh number is high (Ra = 10(7)). The local Nusselt number of solid phase (Nu(sy)) presents symmetrical distribution about the center line of Y direction. The total heat transfer rate Q of case A has a higher value and its increasing rate becomes larger with the increase of porosity. Compared with other thermally active cases, the value of the total heat transfer rate Q of case E is the lowest with an increase of porosity.