Ternary hybrid-nanofluid magneto-convective flow inside the octagonal enclosure with an inner circular obstacle contribution to entropy generation

Natural convection (NC) plays a pivotal role in convective heat transfer (HT) and has been extensively studied. This research focuses on examining the impact of different parameters on HT and fluid flow behavior of a ternary hybrid nanofluid (Al 2 O 3 -Fe 3 O 4 -Cu-H 2 O) under the influence of a magnetic field within an octagonal enclosure containing a circular obstacle. This work investigates HT features of a buoyancy-driven NC flow that is laminar, steady and incompressible. The study also takes into account the entropy generation (E gen ) and the Bejan number (Be) in an octagonal enclosure with an inner circular obstacle for varying boundary conditions. The finite element method is used to numerically solve the governing equations and the associated boundary conditions. A variety of parameter values are employed in this study such as 0% ≤ nanoparticles volume fraction (φ) ≤ 5%, 10 3 ≤ Rayleigh number (Ra) ≤ 10 6 , 0 ≤ Hartmann number (Ha) ≤ 60. The present analysis highlights that the rate of HT and E gen can be improved by adding ternary hybrid nanoparticles within the cavity by 42.9% and 14.89% respectively. However, the average E gen becomes higher for increasing Ra and decreasing Ha at φ a = φ b = φ c = 5%. Moreover, larger nanoparticle volumes result in improved thermal performance, especially when Ra is higher. The ternary hybrid nanofluids for this architecture has the potential to improve thermal management systems by efficiently reducing external heat loss.