Numerical study on thermal performance of Sisko fluid with hybrid nano-structures

Abstract

Sisko fluid rheological correlations accurately determine relationships between stress and strain for polymer fluids. The simultaneous use of rheological stress-strain relations for Sisko fluid and thermophysical properties for pure fluid, nano-structures, and nano-Sisko fluid is a challenge towards numerical simulations. The present investigation has addressed this challenge and successfully implemented the finite element method (FEM) to complex mathematical models. It is a proven fact that FEM for steady problems is stable, convergent, and consistent. Therefore, stable, accurate, and convergent solutions are computed as present problems are steady and well-posed. The parametric investigation is carried out and validated of results is done. The outcomes in form of graphical and numerical outputs are displayed. A significant increase in shear stress and heat flux due to suspension of nano-structures is noticed. However, this increase in shear stress and heat flux because of hybrid nanostructures is greater than the shear stress and heat flux associated with mono nano-Siskofluid. The dissipation of heat due to the friction among the particles of fluid is responsible for increasing the thermal boundary layer thickness. Thus boundary layer thickness for the case of hybrid nanofluid is wider than that associated with mono-nanofluid. The diffusion of species in hybrid nanofluid is slower than the diffusion of species in pure and mono-nanofluid. Magnetic field causes drag on the surface. Therefore, the strength of the surface must afford the drag in order to avoid the failure of the system. Viscous dissipation contributes to enhancing the temperature of fluid particles. Heat generation affects thermal performance adversely, therefore nonheat generation fluid performance as better coolant. The optimized raise in thermal conductivity of Sisko fluid due to the inclusion of hybrid nano-particles is noticed. Therefore dispersion of hybrid nanoparticles is recommended.