Numerical investigation on heat transfer performance of bionic microchannels under a magnetic field

The thermal-hydraulic performance of microchannel heat sinks is investigated with the application of biomimetic micropillars and magnetic nanofluids at Reynolds numbers of 200–500. The pressure drop and maximum wall temperature are validated against published data, with a maximum deviation of 1.36%. The heat transfer performance is enhanced by near-wall fluid mixing and thermal boundary-layer disruption induced by bionic micropillars, under heat fluxes of 1.0 MW/m² and 1.5 MW/m². At an inlet velocity of 1.00 m/s, the overall performance factor of the spoon-shaped microchannel increases by 8.71%, while thermal resistance is reduced by 7.86%. The thermal-hydraulic performance is enhanced with a volume fraction of 2% magnetic nanofluid under magnetic field strengths of 2–8 T. Secondary flow is formed in magnetic nanofluids under a magnetic field. A balance is achieved between strengthened heat transfer and moderated hydraulic losses through magnetic-field regulation. The overall performance factor of the spoon-shaped microchannel is improved by 77.06%, while thermal resistance is reduced by 48.28% at an inlet velocity of 1.00 m/s under magnetic field strengths of 8 T. This study provides a reference for the design of high-efficiency electronic cooling systems.