THE EXERGY EFFICIENCY AND PUMPING POWER OF NANOFLUID THROUGH A HELICALLY COILED TUBE HEAT EXCHANGER UNDER TURBULENT FLOW

This paper theoretically examines the effects of water-Al2O3 nanofluid on exergy destruction, exergy efficiency and pumping power in the helically coiled tube heat exchanger under turbulent flow and subjected constant wall condition. The effects of the nanoparticles volume concentration, nanoparticle dimensions, Reynolds number, curvature ratio and dimensionless inlet temperature considered to be the main parameters in this study. It is found that when the Reynolds number increases, dimensionless total exergy destruction decreases. It is observed that by increasing the nanoparticles volume concentration from 2% to 6%, the dimensionless thermal exergy destruction reduces by 3.64% to 20.21 % compared to pure water. Also, it is seen that when nanoparticles dimensions increases, the exergy efficiency increases and pumping power decreases. Finally, the exergy efficiency increases with increasing of curvature ratio and pumping power decreases with increasing of curvature ratio.