Hydro-thermal analysis of magnetize nanofluid inside pyramid shape enclosure under the effect of non-uniform heating

This study investigates the heat transfer enhancement in a non-uniform magnetize nanofluid flow inside a pyramid shape cavity with hot circular obstacle. Non-uniform heating is applied at the bottom wall, and scaling is used to convert the governing equations into dimensionless form. The Computational Fluid Dynamics (CFD) approach is employed to solve the equations. Numerical results are presented through streamlines and isotherms. The Nusselt number (Nu) and entropy generation are calculated to assess heat transfer. Results show a 4.75 % decrease in heat transfer rate as the nanoparticle volume fraction (φ) varies from 0 to 0.04, and a further 6.31 % reduction as the Hartmann number (Ha) increases from 0 to 20. The Nusselt number for non-uniform heating amplitude $I$ (from 0.5 to 0.9) displays a significant increase of up to 39 % as Hartmann number increases from 0 to 20, while showing an overall decrease of approximately 41 % across frequency ($f$ = 0, 1 and 3) as the $Ha$ increases from 0 to 100. Entropy generation decreases significantly, by approximately 67 % for $\phi$ (0–0.02), 59 % for $I$ (0.05–1) and 57 % for $f$ (0–3), as $Ha$ increases from (0–100). Kinetic energy decreases for increasing frequency $\left(f\right)$, Rayleigh number $\left(Ra\right)$, and inclination angle $\left(\gamma \right)$.