Darcy-Boussinesq convective flow in a trapezoidal enclosure with thermal stratification

We explore numerically the Darcy–Boussinesq convective flow of water, kerosene, and engine oil through the glass ball, aluminum foam and sandstone porous medium inside a right-angle trapezoidal enclosure taking into consideration of thermal stratification. The bottom and left walls of the enclosure are uniformly heated, whereas thermal insulation is considered for the upper wall of it. Thermal stratification is applied to the right wall. The governing nondimensional partial differential equations are simulated using the Galerkin weighted residual finite element method with the help of COMSOL Multiphysics. We explored the time evolution of solutions and investigate the effects of the Rayleigh number, thermal stratification parameter, porosity parameter, types of the solid matrix and working fluids, and on the average Nusselt numbers, streamlines and isotherms. The simulated results confirm that the heat transfer rate amplifies with the increase in Rayleigh number and diminishes with the thermal stratification, porosity and aspect ratio of the enclosure. The results further guarantee that engine oil and aluminum foam perform better for heat transfer intensification. A two-cell flow is obtained for a stronger thermal stratification.