The Behavior of Natural Convection in the Water Saturated Horizontal Porous Layer Including the Maximum Density

Abstract

The upper cooling surface temperature of the layer is fixed at the freezing point of 0°C and the lower heating surface temperature is fixed at a prescribed temperature such as 7, 10, 15, 20, 25 and 30°C in this experiment. The bead diameter employed in the porous layer is 5, 11 and 15 mm for glass beads, and 11 mm for steel beads. The layer depth is fixed at 25, 50, 75, 100 and 125 mm. It is found in this investigation that the Nusselt number decreases with decreasing surface temperature heating at the prescribed Rayleigh number due to the maximum density of water, and the effect of the maximum density on natural convection becomes small when the lower heating surface temperature is larger than about 25°C.