Numerical simulation of MHD mixed convection Copper-Iron Oxides/water hybrid nanofluid over circular concentric tubes

Researchers have explored various design parameters and conditions to identify the most suitable and efficient designs. One area of research that has shown promise is the geometric modification of concentric heat tubes under different conditions. A significant research gap is the implementation of hybrid nanofluids in concentric tubes under MHD, mixed convection changing the various heat transfer parameters. So, the present work examines the impact of the different inner radii of a concentric tube under a magnetic field and mixed convection using copper-iron oxides/water (Cu-Fe ₃ O ₄ /H ₂ O) hybrid nanofluid. The finite element method with nonlinear governmental equations has been employed for this study. The model has been validated from the past literature with minimal numerical error. The controlling parameters for the study are chosen as the inner radius (r1 =0.2, 0.4. 0.6, and 0.8), central angle 30 °≤ γ ≤ 90°, Hartmann number (0 ≤ Ha ≤ 100), Prandtl number (Pr= 0.71, 6.5, 25), Rayleigh number (103 ≤ Ra ≤ 106) and solid volume fractions (ϕ = 0.1, 0.2, 0.3, 0.4, 0.5). The results have been shown as streamlines, isotherm plots, local Nusselt number (Nu) for the inner and outer arc for variable inner radius, Ra, Pr, Ha, central angles and ϕ. The findings show that with the ascends of the inner arc length, the Nu decreases and for the outer arc length, it increases.