Three dimensional unsteady natural convective heat transfer in an inclined cubic enclosure with porous medium is studied numerically. The right side wall (X=1) of the enclosure is kept at a constant temperature of T_o, Temperature of the opposite vertical wall (X=0) varies by sine law with a mean value of T_o. Other walls are kept adiabatic. A Brinkman-extended Darcy model is used to describe flow through porous medium in the enclosure and the equations are solved with SIMPLE algorithm. Inclination angle α1 rotating around Y coordinate varies between 0å and 90°. Inclination angle α2 rotating around X coordinate varies between 0° and 45°. Dimensionless temperature oscillation frequency f ranges from 5° to 90π. Effects of inclination angles and temperature oscillation frequency on heat transfer are studied in detail. It shows that the maximal heat transfer is achieved at an inclined angles α1=46°, α2=45° and a temperature oscillating frequency f=45π.

We study heat transfer and fluid flow in a complex enclosure fiLled with porous media, with SIMPLEC (Semi-Implicit Method for Pressure Linked Equations Consistent) algorithm in curvilinear coordinates. The upper and lower walls of the enclosure are horizontal and adiabatic. The vertical wall forms cosine curve and is kept at a constant temperature. Governing equations are discretized with a finite-volume method on body-fitted coLlocated grids. Brinkman-extended-Darey model and local thermal non-equilibrium model are used to solve momentum and energy equations. Effects of parameters, such as Rayleigh numbers, Darey numbers and porosity, on heat transfer and fluid flow are studied. It is shown that Rayleigh numbers and Darey numbers have significant effect while porosity is negligible. There exists an optimal aspect ratio to make the heat transfer rate maximum.

Unsteady natural convection heat transfer of incompressible fluid in an inclined cavity filled with saturated porous medium is studied numerically.The temperature of the cold sidewall maintains constant and the temperature of the opposite sidewall varies sinusoidally with time.The Brinkman-extended Darcy model and SIMPLER algorithm are adopted.Comprehensive numerical solutions are acquired at a fixed Prandtl number Pr=1 and a Rayleigh number Ra=10⁶.The inclination angle of the enclosure α varies from 0° to 90°.The effects of α and dimensionless oscillation frequency f on the natural convection are analyzed.The maximum heat transfer is reached at f=60π and α=43°.

Periodically fully developed convective heat transfer characteristics in a two-dimensional wavy channel are investigated numerically with a constant wall temperature.The calculations are performed with Pr=0.7,Re=20~500 on non-orthogonal non-staggered grids generated by an elliptic equation system.A semi-implicit method for pressure linked equations revised (SIMPLER) algorithm in curvilinear body-fitted coordinates is employed.Effects of Reynolds number and geometric parameters,such as aspect ratio φ and shape ratio γ,on heat transfer and friction factor are studied.It shows that no recirculation region occurs through the whole channel at low Reynolds numbers,small aspect ratio or small shape ratio.With the increase of Reynolds number,aspect ratio or shape ratio,heat transfer is enhanced due to flow recirculation.Corresponding friction factor increases simultaneously.