Heat transfer in MHD stagnation point flow of a ferrofluid over a stretchable rotating disk

In this article, heat transfer analysis in three dimensional boundary layer stagnation point flow of incompressible ferrofluid over a stretchable rotating circular disk in the presence of uniform external magnetic field has been investigated. For this purpose, three different types of ferroparticles namely, magnetite (Fe3O4), cobalt ferrite (CoFe2O4) and Mn-Zn ferrite (Mn-ZnFe2O4) are considered with water as a base fluid. The governing partial differential equations of the considered problem are transformed into non-dimensional ordinary differential equations using similarity transformation (Turkyilmazoglu, 2012). The solution of obtained equations is computed numerically using an efficient implicit finite difference scheme. The effects of pertinent parameters namely, volume fraction parameter of magnetic nanoparticle, rotating parameter, magnetic parameter, velocity ratio parameter and Prandtl number on both radial and azimuthal velocity profiles, temperature profile, skin friction coefficients and local Nusselt number are computed and shown through graphs and tables. For magnetite ferroparticle (Fe3O4) radial velocity decreases and azimuthal velocity and temperature increase with increasing value of volume fraction parameter phi. The values of skin friction coefficient in radial direction and local Nusselt number of magnetite ferroparticle (Fe3O4) become higher than that of other ferroparticles due to the maximum density and thermal conductivity. (C) 2016 Elsevier B.V. All rights reserved.