Numerical investigation of ferrohydrodynamic magnetic nanofluid convection in a trapezoidal cavity channel

The Efficient dissipation of heat in various heat exchanger geometries, particularly rectangular channels incorporating cavity features, remains a critical challenge in thermal engineering. This research investigates a novel heat transfer augmentation strategy by analyzing the combined influence of a trapezoidal cavity, Fe 3 O 4 nanofluids, and induced ferrohydrodynamic body forces on convective transport within such channels. The primary goal of this investigation was to determine the quantitative correlation between alterations in magnetic field intensity and significant efficiency indices, the spatially averaged Nusselt number, hydrodynamic pressure losses, and a comprehensive (PEC), across a variety of Reynolds numbers. The steady-state Navier-Stokes-Fourier equations were numerically solved using ANSYS Fluent's built-in finite volume solver. The base fluid was enhanced with Fe 3 O 4 nanoparticles, dispersed at a volume fraction of 0.02, to augment its effective thermal conductance. Simultaneously, externally applied magnetic fields, ranging from 800 to 1400G, were strategically employed to induce ferrohydrodynamic body forces arising from nanoparticle magnetization. The findings indicate a substantial augmentation of the Nu with elevation intensity of the magnetic field, exhibiting enhancements of up to 244% at Re=300 and the maximum applied field strength compared to the field-free baseline. Counterintuitively, a concomitant reduction in pressure drops, approaching 50%, was observed with increasing field strength, an effect ascribed to the suppression of turbulent eddies and the induction of a more laminarized flow profile through the action of the Magnetic body force. PEC analysis confirmed the synergistic effect of nanofluids and magnetic fields, resulting in a net enhancement of thermal performance without incurring substantial penalties in flow resistance. These findings underscore the significant potential of ferrohydrodynamic effects in optimizing heat transfer within rectangular channel architectures. • Ferrohydrodynamic convection is analyzed in a trapezoidal cavity channel. • Fe 3 O 4 -water nanofluid subjected to an external magnetic field. • Enhanced heat transfer performance compared with the base fluid. • The influence of cavity geometry and magnetic field intensity is examined.