On steady MHD flow and heat transfer past a rotating disk in a porous medium with ohmic heating and viscous dissipation

Abstract

Purpose – The purpose of this paper is to investigate the hydromagnetic steady flow and heat transfer characteristics of an incompressible viscous electrically conducting fluid past a rotating disk in a porous medium with ohmic heating, Hall current and viscous dissipation are also investigated. Design/methodology/approach – Using appropriate similarity variables and boundary-layer approximations, the fluid equations for continuity, momentum and energy balance governing the problem are formulated. These equations are solved numerically by using the most effective Newton-Raphson shooting method along with fourth-order Runge-Kutta integration algorithm. Findings – It was found that magnetic field retards the fluid motion due to the opposing Lorentz force generated by the magnetic field. Both the magnetic field and the Eckert number tend to enhance the heat transfer efficiency. The Hall parameter however reduces the heat transfer rate. In terms of the friction coefficient, the magnetic interaction parameter, the Hall parameter and the Eckert number all combine to increase the skin friction, while increasing the Darcy number (increasing permeability) reduces the skin friction so increasing the fluid velocity. Practical implications – This paper provides a very useful source of information for researchers on the subject of hydromagnetic flow in porous media. Originality/value – This type of problem has potential to serve as a prototype for practical swirl problems, for example, axisymmetric flow in combustors.