Assessment the Effect of Nanofluid on Turbulent Heat Transfer and Pressure Drop in Bend Finned Tube

Abstract

An experimental study of using Al2O3-water nanofluid that flows in a finned bend tube cross flow heat exchanger on heat transfer and pressure drop was implemented. The experimental part consists of closed loop of water or nanofluid that flows in the bend tube heat exchanger that inserted in an air wind tunnel. The effect of different nanoparticles volume fraction of (0, 0.01, 0.05, 0.1 and 0.2%Vol.) were depressed in deionized water. The hot water or nanofluid flow in the two types of smooth and finned bend tube heat exchanger with different inlet Reynolds numbers for the range of (450-920) for laminar flow and (6900-10000) for turbulent flow. The experimental results were presented as a friction factor, local and average Nusselt number for the water and air side respectively for the smooth and finned bend tubes. The results show that the inner average Nusselt number of Al2O3-water nanofluid that flows in heat exchanger enhanced by up (34.6 %) for smooth tube heat exchanger and about (44.1 %) for finned bend tube heat exchanger compared to pure water. Also, the friction factor of the nanofluid flow inside the heat exchanger increase by up (13.9 %) for smooth bend tube heat exchanger and (22%) for finned bend tube as compared with the use of pure water.