Heat transfer and friction factor investigations of CuO nanofluid flow in a double pipe U-bend heat exchanger

Experimental investigation was conducted for the estimation of convective heat transfer and friction factor of CuO nanofluids flow in a double pipe U-bend heat exchanger under turbulent flow conditions. The CuO nanofluid was flow through the inner tube of U-bend heat exchanger at different mass flow rates (8, 10, 12 and 14 LPM) and at different volume concentrations (0.01%, 0.03% and 0.06%). The hot water was flow through the annulus tube at a fixed mass flow rate of 8 LPM. The results indicate that, the Nusselt number of nanofluids increases with increase of Reynolds number and particle volume concentrations. The Nusselt number enhancement is about 18.6% at 0.06% volume concentration when compared to base fluid with a pumping penalty of 1.09-times. (C) 2019 Elsevier Ltd. All rights reserved.