Entropy generation, magnetohydrodynamic conjugate mixed convection with Joule heating and rotohydrodynamic effects of a ferrofluid in a vented chamfered domain

A comprehensive numerical study is conducted on magnetohydrodynamic mixed convection and entropy generation in a vented chamfered cavity filled with Fe 3 O 4 -water ferrofluid. The enclosure contains a rotating heat-generating cylinder, and simulation examine the effects of cylinder diameter, angular velocity, and spatial placement under varying Grashof (10 4 - 10 7 ), Reynolds (100 - 3162.28), and Hartmann (10 - 56.23) numbers. The governing equations are solved via the Galerkin finite element method in COMSOL Multiphysics, which incorporates Joule heating and thermophysical coupling. The results show that increasing the cylinder diameter enhances the Nusselt number, but also increases the entropy. Aiding rotation ( Ω = 5) promotes strong circulation and low entropy, whereas opposing rotation ( Ω = –5) increases wall shear and heat transfer at the expense of irreversibility. Cylinder positioning influences global thermal behavior, with near-inlet placement yielding the highest ecological coefficient of performance at high Gr . The findings offer practical insights for the design of compact, energy-efficient ferrofluid-based thermal management systems under MHD effects. • Entropy generation in ferrofluid flow analyzed inside a vented chamfered cavity. • Combined effects of magnetohydrodynamics, Joule heating, and roto-hydrodynamics studied. • Governing equations solved dimensionally using COMSOL Multiphysics. • Chamfered geometry enhances heat transfer and reduces irreversibility. • Provides new insights into ferrofluid energy efficiency under magnetic influence.