Thermal-hydraulic performance of water containing carbon nanotubes and
alumina nano-additives inside a parabolic through solar collector with
turbulators
Abstract
Current study investigates thermal-hydraulic performances of turbulent
forced hybrid nanofluid flow and heat transfer inside a parabolic
through solar collector equipped with turbulators. The main aim of
present work is to simulate and investigate the effects of different
Reynolds numbers and geometrical parameters on thermal and hydraulic
characteristics of the system to achieve the maximum PEC value. The heat
transfer fluid is water-based MWCNT-Al2O3 (80%:20%) hybrid nanofluid
which makes a Newtonian nanofluid. The RANS equations with the
shear-stress (SST) k–ω turbulence model have been employed for modeling
the turbulence regime. Based on obtained results, usage of turbulators
leads to higher thermal diffusion because of destroying the laminar sub
layer, increasing heat transfer surface and convection heat transfer.
For θ=180°, the maximum values of average Nusselt number (Nuave) are
achieved during all studied range of Reynolds numbers followed by θ=90°
and θ=0°, respectively. For HO=15mm, the maximum values of Nuave are
achieved followed by HO=10mm and HO=5mm, respectively. The model with
HO=5mm has not the maximum Nuave; but, it has lower pressure drop than
HO=15mm. For BO=1000mm, the maximum values of Nuave are achieved
followed by BO=800mm and smooth channel, respectively. Furthermore, for
δ=60°, the maximum Nuave are achieved followed by δ=40° and δ=20°,
respectively. For model δ=40° the maximum values of PEC are achieved
followed by smooth channel, δ=20° and δ=60°, respectively. The parabolic
through solar collector model with θ=180°, HO=15, BO=1000mm, δ=40° and
bO=20mm filled with hybrid nanofluid suggested as the optimum model in
the present investigation.