Semi-empirical relation for forced convective analysis through a solar collector

A numerical study has been conducted to investigate the forced convection through a flat plate solar collector. The water alumina nanofluid is used as the working fluid inside the riser pipe of the solar collector. The governing differential equations with boundary conditions are solved by finite element method using Galerkin's weighted residual scheme. The effects of major system parameters on the forced convection heat transfer are simulated. These parameters include the the Reynolds number (Re) and Prandtl number (Pr). Comprehensive average Nusselt number, average temperature, mean velocity, percentage of collector efficiency, mid-height temperature for both nanofluid and base fluid through the collector pipe are presented as functions of the governing parameters mentioned above. The numerical results show that the highest heat loss rate is observed for both the largest Re and Pr. Percentage of collector efficiency enhances for growing Re and falling Pr. A correlation is developed among average Nusselt number, Reynolds number and Prandtl number. Then a semi-empirical relation is established from this correlation with experimental data found in the literature. (C) 2014 Elsevier Ltd. All rights reserved.