Hierarchical sintered porous surfaces with enhanced pool boiling heat transfer performance for high-power cooling applications

Porous surfaces fabricated by sintering maintain good pool boiling heat transfer performances and have the advantages of high processing efficiency and low cost. Hierarchical sintered porous structures (HS) composed of copper mesh and porous column array are fabricated by a sintering process. Chemical oxidation and high-temperature reduction are used to deposit micro/nano coating on HS (NHS). The porous column array induces the capillary value effect and enhances the capillary performances of HS and NHS. The micro/nano coating provides more nucleation sites and further enhances the capillary velocity. The faster capillary velocity and higher volumetric flow rate of HS and NHS result in much higher critical heat flux (CHF) than sintered mesh surfaces (MS). The CHF of NHS reaches 2422.9 kW/m2, which is 43.7 % and 21 % higher than that of MS and HS, respectively. A good linear relationship between the volumetric flow rate and the CHF is observed. Besides, the porous structures greatly enhance the heat transfer coefficient (HTC). The micro/nano coating of NHS has a more obvious enhancement effect on HTC at low heat fluxes. The pool boiling heat transfer performance of HS and NHS is comparable to or even better than those in literature and has the feasibility of application in high-power cooling scenarios.