Influence of Variable Fluid Density on Free Convection in Rectangular Porous Media

Free convection in rectangular porous media has been numerically investigated incorporating the dependence of fluid density on temperature in all the conservation equations. The fluid density dependence on temperature is described through a parametric equation which can be used for different fluids. The method of successive accelerated replacement scheme has been employed to obtain numerical results for a wide range of Rayleigh numbers, 50 to 1000, aspect ratio, 0.1 to 10 and density difference ratio of 0 to 0.75. The increase in the average Nusselt number at a Rayleigh number of 100 and an aspect ratio of unity is 9.57 percent when density difference ratio is 0.25, whereas it is as high as 19.88 percent when the density difference ratio is 0.5.