Effect of radiation on convective flow in a tilted solar collector filled with water-alumina nanofluid

Abstract

The effect of radiation on natural convective flow inside a solar collector having a flat-plate cover and a sine-wave absorber is analyzed numerically. The solar collector is filled with water-Al₂O₃ nanofluid. The governing differential equations with boundary conditions are solved by the Penalty Finite Element Method using Galerkin’s weighted residual scheme. The effects of radiation (ε) and tilted angle (ψ) on the flow and heat transfer characteristics are simulated. In addition average Nusselt number, average temperature and mean velocity field for nanofluid within the collector are presented graphically for the governing parameters mentioned above. The highest heat transfer rate is observed for the largest ε and absence of ψ. The Al₂O₃ nanoparticles with the highest ε and in absence of ψ are established to be most effective in enhancing performance of heat transfer rate. Moreover, increasing tilted angle ψ and lessening emissivity ε cause decrease of average fluid temperature. For growing both parameters mean velocity field increases.

Keywords: Radiation, tilted solar collector, finite element method, water- alumina nanofluid