title: Nanofluid impingement jet heat transfer.
abstract: Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters.
authors.affiliation: King Saud University, Mechanical Engineering Department, King Abdullah Institute for Nanotechnology, 800 Riyadh, 11421, Saudi Arabia. ozeitoun@ksu.edu.sa.
authors.forename: Obida
authors.initials: O
authors.lastname: Zeitoun
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ali