Enhanced boiling heat transfer via microporous copper surface integration in a manifold microgap

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Heat flux dissipation from electronic devices has increased with their miniaturization owing to the increasing performance demands and development of microfabrication technologies. Improving the heat transfer performance is crucial for enhancing heat dissipation. However, this often leads to an increase in pressure drop, which reduces energy efficiency. Microgap heat sink is a promising approach in this regard owing to its geometrical simplicity and facile fabrication while providing heat transfer performance comparable to that of microchannel heat sinks with substantially lower pressure drops. In this study, we develop a manifold microgap heat sink integrated with a porous copper surface that effectively enhances heat transfer while using significantly low pumping power. A three-dimensional liquid routing manifold is used to achieve better flow distribution and alleviate temperature non-uniformity while providing improved heat transfer by enabling jet impingement and mixing of the thermal boundary layer on the microgap surface with minimal additional pressure drop. Moreover, a microscale inverse opal structure is used to facilitate nucleate boiling on the microgap surface, which improves heat transfer while maintaining a relatively low flow resistance. A maximum heat flux of 322.8 W/cm2 was achieved at the mass flux of 472 kg/m2 s, and the corresponding pressure drop and maximum heater temperature were 0.6 kPa and 140 ℃, respectively. The coefficient of performance (COP) achieved herein was significantly higher than those reported in previous relevant studies, indicating that the proposed cooling technique can potentially be used for energy-efficient thermal management in electronics devices.