Magnetohydrodynamic flow and heat transfer of Casson ternary nanofluid over a vertical cone: A Keller box method study

In this study, the magneto-hydrodynamic boundary-layer flow and thermal convection of the Casson fluid with a ternary nanofluid mixture over a vertical cone is presented. The Casson model is used for modeling non-Newtonian yield stress fluids, which are present in polymeric and industrial fluids. The effects of an external magnetic field, thermal and momentum slip conditions, and non-uniform heat source/sink are considered, and the model is applicable to realistic thermal processing and energy applications. Conservation of mass, momentum, and energy equations are derived in the vertical cone geometry and converted to a dimensionless similarity form. Accurate velocities and temperatures inside the boundary layer are numerically calculated with the resulting nonlinear system solved numerically by a stable finite-difference method. Results show that because of the applied magnetic field, the fluid motion is slowed down in the boundary layer, and the thermal energy in the same region is increased by a resistive Lorentz force. The addition of ternary nanoparticles resulted in remarkable improvements in effective thermal conductivity and, hence, better heat transfer performance as compared to traditional fluids. With the help of momentum slip, the wall shear stress is reduced, while thermal slip enhances the reduction of the surface heat transfer rate. Moreover, the heat source parameter is non-uniform and increases the field of temperature, and the heat sink parameter decreases the field of temperature. The interplay of magnetic forces, Casson rheology, ternary nanoparticle effects, and slip mechanisms is of crucial importance to control the convective heat transfer over a vertical cone.