Secondary vortex drag reduction and heat transfer enhancement of nanofluids in hierarchical microchannels applied to thermal management of electronic components

Abstract

In order to improve the heat dissipation performance of electronic components, two hierarchical microchannel structures with curve and straight corners are proposed, and semi-circular and trapezoidal secondary flow structures are introduced into the structure with the best performance. The effects of coolant (Fe3O4-water nanofluid), layered structure and secondary flow structure on the comprehensive performance of MCHS were studied by numerical simulation. Results showed that deionized water is more suitable for the heat dissipation of microchannels at this scale. The hierarchical structure has the effect of enhancing heat transfer, and Nu can be increased by up to 67.32 %. The introduction of secondary flow structure has drag reduction effect in a certain Reynolds number range. The hierarchical MCHS with semi-circular secondary flow structure has drag reduction effect in the Reynolds number range of Re = 200–400, and the pressure drop can be reduced by up to 1.89 %. The hierarchical MCHS with trapezoidal secondary flow structure always has a drag reduction effect in the range of Reynolds number Re = 200–600, and the maximum pressure drop can be reduced by 2.46 %, showing excellent drag reduction ability. In addition, the introduction of trapezoidal secondary flow in MCHS increases the Nusselt number by 9.70 %, the comprehensive performance index reaches 1.10, and the cooling performance and comprehensive performance are optimal. The combination of hierarchical structure and secondary flow structure has excellent drag reduction and heat transfer enhancement effects, and has broad application prospects in the field of thermal management of electronic devices.