Free Convection of Williamson Hybrid Ferrofluids Over a Sphere with Viscous Dissipation

Abstract

This paper investigates the convective flow and heat transfer characteristics of a non-Newtonian hybrid ferrofluid over a spherical geometry incorporating the effects of viscous dissipation effect. A Williamson hybrid ferrofluid formed by embedding gold nanoparticles and magnetite nanoparticles in a blood which serves as a Williamson base fluid, is scrutinized. The mathematical model of the fluid flow is governed by a set on non-linear partial differential equations. These equations are transformed into a more manageable form before solving it numerically by using the Keller-box method. The study presents graphical analyses of the thermal and flow behavior, including the reduced Nusselt number, skin friction coefficients and corresponding temperature and velocity profiles. The influence of the Eckert number and nanoparticle volume fraction on the flow and thermal behavior is thoroughly examined and discussed. In conclusion, hybrid ferrofluids with gold and magnetite nanoparticles significantly enhance convective heat transfer as shown by higher Nusselt number. The Williamson parameter increases shear stress but lowers the heat transfer, while the Eckert number causes viscous heating that slightly raises Skin friction coefficient but significantly lowers heat transfer efficiency, and magnetic parameter raises flow resistance while suppressing convection. The study aims to provide insights into enhancing thermal performance in engineering and biomedical applications where spherical geometries and hybrid nanofluids are relevant.