Nanofluids are a new category of heat transfer fluids which show great potentials for enhancement of heat transfer. Enhancement of heat transfer with minimization of thermal devices requires the use of nanofluid. In this investigation, much effort was carried out to measure the heat transfer parameters of ?-Al 2 O 3 / water nanofluid such as Nusselt number and heat transfer coefficient through turbulent double pipe heat exchanger with counter current and co-current configurations. The effect of different parameters such as Reynolds number, Graetz number and nanoparticles volume fraction on convective heat transfer coefficient and Nusselt number of nanofluid were investigated. The results showed an increase in these parameters in comparison with those of pure distilled water.
