New empirical correlations for Nu and f of nanofluids were developed. The Nusselt number (Nu) increased upto 40% along with a maximum increase of 28.57% in f as compared to their basefluid. Heat transfer and friction factor (f) were increased with enhancing concentration and Re. Maximum 13% enhancement in k and a maximum of 20% enhancement in were obtained at 0.35 vol.% as compared to basefluid. Thermo-physical properties namely conductivity (k) and viscosity () of NF were determined at various temperatures range of 25-65 C. Experiments are conducted in the Reynolds number (Re) range of 2798.96-27989.62 maintaining the bulk temperature of the flow at 45 C. An aqua based dispersion of SiO2 nanopowder with 16.58 nm average particle diameter were used as the working fluid with 0.15-0.35 vol.%. The thermo-fluidic performance of SiO2-water nanofluid (NF) flow inside a horizontal tube of circular cross section were examined applying constant heat flux.

This implies that turbulence has a Heat Transfer. However, at higher Reynolds numbers when the flow is turbulent, Al 2 O 3-based nanofluids demonstrate better performance having a percentage increase in Nusselt numbers equal to 40% and 23% as compared with CuO and SiO 2-based nanofluids respectively under the same Reynolds number of 15,000.

Results suggest that under a laminar flow regime with the same Reynolds number of 2000, CuO-based nanofluids perform better as compared with SiO 2 and Al 2 O 3-based nanofluids with Nusselt number (Nu) having percentage increase of 90% and 60% comparing with SiO 2-and Al 2 O 3-based nanofluids, respectively. Several simulations were performed from low to high Reynolds numbers, corresponding to laminar and turbulent flow regimes using ANSYS-Fluent CFD solver. This study is based on the numerical investigation of different types of nano-fluids, consisting of CuO (50 nm), SiO 2 (40 nm), and Al 2 O 3 (15 nm) nanoparticles at different volume concentrations. In recent studies, much attention has been given to nanofluids suggesting that adding nanoparticles in base fluids offers a higher heat transfer rate compared with conventional fluids.

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