Numerical investigation of synergistic effects of magnetic fields and bluff bodies on heat transfer enhancement and pressure drop reduction in microchannels

Efficient thermal management is essential for designing compact and high-performance heat sinks and heat exchangers. This study addresses the challenge of optimizing heat transfer while minimizing pressure losses in systems exposed to concentrated heat flux by proposing a novel approach that employs both active and passive vortex generators. Specifically, a uniform magnetic field generated by permanent magnets and a bluff body are utilized within a microchannel containing a 2 vol% ferrofluid. Numerical simulations were performed across Reynolds numbers ranging from 100 to 500 and magnetic field intensities up to 0.5 T to evaluate the system's performance. The results demonstrate that the combination of magnetic fields and a bluff body induces vortex generation, alters velocity distribution, and enhances flow mixing, resulting in a 30 % increase in heat transfer efficiency and an 11 % reduction in pressure drop under optimal conditions. Although the introduction of barriers led to a 3 % rise in pressure drop, the uniform magnetic field effectively mitigated friction by reducing flow separation and limiting surface contact. These findings highlight the potential of this method for improving the design of advanced thermal management systems. • Innovative use of active and passive vortex generators enhances heat transfer in microchannels. • Permanent magnets create recirculation zones, significantly boosting heat transfer efficiency. • Magnetic field intensity and bluff body optimize heat transfer, achieving a 30 % improvement. • Combined magnetic field and obstacle reduce pressure drop by 11 % under optimal conditions. • Without the obstacle, a 14 % pressure drop was observed, highlighting the trade-off in system efficiency.