The natural convection around a heated trapezoidal block of different sizes positioned centrically in a larger trapezium has been investigated numerically. The annulus between the
trapeziums is occupied by porous media. The sides of the inner trapezium are heated to a fixed temperature and the slanted walls of the outer trapezium are isolated thermally. In contrast, its upper and lower walls are heated uniformly. The pertinent dimensionless equations were solved with
COMSOL Multiphysics 5.6. The parameters considered are modified Rayleigh number, Darcy number, and area ratio. The results of this study are shown as isothermal contours, stream functions, and average Nusselt number. The results show that increasing the modified Rayleigh number improves heat transfer; however, the response of the thermal profiles to area ratio increment depends on the range of Darcy number considered. This study finds application in ingot treatments and microchannel cooling, among others
