Experimental study of nanofluids natural convection heat transferin various shape pores of porous media

This research investigates the influence of various shape pores of porous media (circular, hexagonal, and square) on nanofluids' natural convection heat transfer. The experimental setup comprises a cube-shaped heat transfer chamber with two opposing hot and cold walls, while the remaining walls are adiabatic. The nanofluids used include Al2O3-water, and TiO2-water, each at two volumetric concentrations of 0.5% and 1%. The heat transfer performance was evaluated at three inclination chamber angles (0, 30, and 60 degrees) toward the hot wall. The results reveal that the highest values of heat transfer coefficient and Nusselt number for all nanofluids and porous media occur at a chamber angle of 30 degrees, while the lowest values occur at an angle of 0 degrees. The highest values of heat transfer coefficient, Nusselt number, Nu* (illustrating the combined effect of porous medium and nanofluids on the Nusselt number of distilled water) are observed for the porous medium with square porosity, while the lowest values of these parameters are associated with the porous medium with circular porosity. Subsequently, all other cases encompassing the influence of angles and volumetric concentration percentages of nanofluids were meticulously investigated and analyzed.