Nanofluid flow and heat transfer in a rotating system in the presence of a magnetic field

In this paper the magnetohydrodynamic (MHD) nanofluid flow and heat transfer between two horizontal plates in a rotating system is analyzed. The lower plate is a stretching sheet and the upper one is a solid permeable plate. The basic partial differential equations are reduced to ordinary differential equations which are solved numerically using the fourth-order Runge-Kutta method. Different types of nanoparticles such as copper, silver, alumina and titanium oxide with water as their base fluid have been considered. Velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number are determined numerically. The influence of pertinent parameters such as nanofluid volume fraction, magnetic parameter, wall injection/suction parameter, viscosity parameter and rotation parameter on the flow and heat transfer characteristics is discussed. The results indicate that, for both suction and injection the Nusselt number has a direct relationship with the nanoparticle volume fraction. The type of nanofluid is a key factor for heat transfer enhancement. The highest values are obtained when titanium oxide is used as a nanoparticle. Also it can be found that the Nusselt number decreases with the increase of the magnetic parameter due to the presence of Lorentz forces. (C) 2013 Elsevier B.V. All rights reserved.