A Study of Forced Convection in Non-Newtonian Hybrid Nanofluids Embedded in a Heated Cylinder Within a Hexagonal Enclosure by Finite Element Method

Nanofluids have the proven capacity to significantly improve the thermal efficiency of a heat exchanging system due to the presence of conductive nanoparticles. The aim of this study is to simulate the forced convection on a non-Newtonian hybrid with a nanofluid (Al 2 O 3 -TiO 2 -H 2 O) in a hexagonal enclosure by the Galerkin finite element method (GFEM). The physical model is a hexagonal enclosure in two dimensions, containing a heated cylinder embedded at the center. The bottom, middle left, and right walls of the enclosure are all considered cold ( T c ), while the top wall is considered to be moving, and the remaining middle, upper left, and right walls have the adiabatic condition. The Prandtl number ( P r = 6.2 ), Reynolds number ( R e = 50, 100, 300 and 500), power law index ( n = 0.6 , 0.8 , 1.0 , 1.2 and 1.4 ), volume fractions of nanoparticles ( ϕ = 0.00 , 0.01 , 0.02 , 0.03 and 0.04 ), and Hartmann numbers ( H a = 0, 10, 20 and 30) are considered in the model. The findings are explained in terms of sensitivity tests and statistical analysis for various R e numbers, n , and H a numbers employing streamlines, isotherms, velocity profiles, and average Nusselt numbers. It is observed that the inclusion of ϕ improves the convective heat transfer at the surging values of R e . However, if the augmenting heat transfer requires any control mechanism, integrating a non-zero H a number is found to stabilize the system for the purpose of thermal efficacy.