UNSTEADY NUMERICAL INVESTIGATION OF FERROFLUID FORCED CONVECTION OVER A DOWNWARD STEP CONTAINING A ROTATING FINNED CYLINDER

Abstract

The unsteady investigation of ferrofluid flow forced convection over a downward step containing a rotating finned cylinder is conducted numerically. The dimensionless partial differential equations of conservation equations for mass, momentum and energy and the boundary conditions associated with them are solved by using the finite element method. Two control parameters are used, the angular velocity Ω (-5, -3, -1, 0, 1, 3, 5) and the Reynolds number Re (10, 20, 50, 100), and their effect as a function of time on flow characteristics and heat transfer is presented. To understand how the rotation of the finned cylinder and Reynolds number affects the heat transfer and fluid flow characteristics, an analysis is made and the results obtained are presented qualitatively by the streamlines and the isotherms and quantitatively by calculating the average and local Nusselt number. It has been observed that the rotation of the finned cylinder enhanced heat transfer significantly. A difference of 177.33% improvement is observed between a rotational speed of a finned cylinder (Ω = -5) in the present paper and that of a cylinder without fin (Ω = 25) in the reference paper.