石墨烯/镍复合微结构表面的池沸腾传热特性

采用电刷镀和表面改性技术，在紫铜表面制备了纯镍微结构（TS1）、亲水性石墨烯/镍复合微结构（TS2）以及疏水性石墨烯/镍复合微结构（TS3）。采用扫描电镜和接触角测量仪分别对三类微结构的表面形貌和润湿性进行了表征；以去离子水为工质，对三类微结构表面的池沸腾传热特性进行了实验研究，发现含有石墨烯的TS2和TS3较TS1的沸腾传热性能均显著改善，其中，TS3具有最大的传热系数和最高的临界热流密度，与TS1相比，其最大传热系数和临界热流密度分别提高了135%和97%。分析表明，TS3具有复杂三维堆叠微结构，疏水性微结构减小了气泡成核的活化能，增加了核化密度，是传热系数提高的主要因素，同时，三维堆叠微结构增加了受热表面的毛细吸液再润湿能力，是临界热流密度提高的主要机理。

Pool boiling heat transfer characteristics on graphene/nickel composite microstructures

Using electric brush plating and surface modification technology, nickel microstructures (TS1), hydrophilic graphene/nickel composite microstructures (TS2) and hydrophobic graphene/nickel composite microstructures (TS3) were fabricated on bare copper surfaces. The morphology and wettability were characterized by scanning electric microscope and contact angle tester. Using deionized water as the working fluid, the pool boiling heat transfer characteristics on these three microstructures were investigated experimentally. It was found that boiling heat transfer performances for the TS2 and TS3 which contained graphene were obviously superior to TS1. The TS3 had the maximum heat transfer coefficient and critical heat flux. Compared to TS1, the maximum heat transfer coefficient and critical heat flux of the TS3 were increased by 135% and 97%, respectively. It was analyzed that TS3 possessed complex 3D superhydrophobic microstructures, which could lower the cavitation energy and increase the bubble nucleation density, resulting in the heat transfer enhancement. Meanwhile, the complex 3D microstructures promote the capillary liquid suction and rewetting ability to the heated surface, which is the major mechanism for the critical heat flux enhancement.