Enhanced Thermo-Fluidic Performance of Aqueous SiO2 Nanofluid Flow Through a Horizontal Tube—An Experimental Investigation

Abstract

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