Modeling the Effect of Porosity on a Solar Water-cooled Coil Filled with Water and Al2O3 Nanofluid

This study focuses on the flow analysis of alumina nanofluid with volumetric ratios of 2% and 4% into non-porous and porous thermal coils under solar heat flux.. Furthermore, the comprehensive study of the nature of boundary layers, the pressure and velocity distributions, and the thermal effects inside the metal porous coil are discussed. To solve the problem, the equations of continuity, momentum, and energy for nanofluid into non-porous and porous coils are used. The comparison between results of average Nusselt number at the present model and experimental data for a non-porous coil shows an acceptable agreement with maximum error of 10.5%. In porous coil, increasing the volumetric ratio of nanofluid has resulted in an increase in the pressure losses where these largest values occurred at 4% volumetric ratio with a value of 4.4 bar. By increasing the volumetric ratio, the amount of convection heat transfer coefficient and Nusselt number are raised and, consequently, the transferred heat into the porous thermal coil will increase.