Enhancement of nanofluid heat transfer in a mini-tube using SiO2 nanoparticles

Abstract

ABSTRACTThis study is aimed to investigate the effect of SiO2/distilled (DI) water nanofluids on the heat transfer enhancement inside a circular mini-tube tube with an inner diameter (Di) = 0.8 mm. The flow was run at fully laminar flow with Reynolds number (Re) = 112. The initial temperatures at all channels were maintained at 50°C as uniform heat flux was applied to the outer surface of the mini-tube. Different weight concentrations (wt%) of silica/water nanofluids (0.1, 0.2, 0.3, 0.4, 0.5 wt%) were used in the experiment. The results concluded that the heat transfer coefficient and Nusselt number were significantly enhanced using silica nanofluids as compared to distilled water as heat transfer fluids. Higher values of heat transfer coefficient and Nusselt number indicate that more heat is being transferred from the tube to the fluid which results in a significant reduction of the overall outer tube surface temperature. The heat transfer enhancement was found to be dependent on the nanoparticle concentrations. The maximum heat transfer coefficient of the nanofluids was achieved using 0.5% silica nanofluids at axial location (Z/Di) = 51.25 with a value of 257.14 W/m2.K.