Modifying the surface wettability at the solid-liquid interface can significantly improve flow boiling heat transfer. The graphene nanoplatelets (GNPs) and epoxy additives form nanocomposites coatings with tunable wettability (superhydrophilic, superhydrophobic and hydrophobic) via a thermal curing process. They are applied for enhancing the subcooled flow boiling heat transfer in a minichannel. By comparing with the uncoated surface, the superhydrophilic GNPs coating shows the highest boiling heat transfer coefficient with a maximum enhancement of 64.9 %. The nanocapillary-networks of the superhydrophilic GNPs coatings facilitate the fast water permeation effect and induce an effective filmwise boiling heat transfer. Moreover, the superhydrophilic GNPs coatings facilitate bubble detachment process and suppress the formation of dry spot during the boiling process. On the contrary, the hydrophobic and superhydrophobic GNPs coatings act as impervious blankets for the intercalation of water and deteriorate the flow boiling rates. The effects of the subcooled degree and the mass flux of the bulk flow on the performance enhancement are also investigated. This study aims to investigate the flow boiling enhancement attributed to the graphene functionalized coatings and provides interesting insights of the ultrafast water permeation mechanism of graphene into the subcooled flow boiling heat transfer.

改变固液界面的表面润湿性可以显着改善流动沸腾传热。石墨烯纳米片 (GNP) 和环氧树脂添加剂形成具有可调润湿性（超亲水、超疏水和疏水）的纳米复合涂层，通过热固化过程。它们用于增强微通道中的过冷流沸腾传热。通过与未涂层表面相比，超亲水 GNPs 涂层显示出最高的沸腾传热系数，最大增强为 64.9%。超亲水 GNPs 涂层的纳米毛细管网络促进了快速的水渗透效应并诱导了有效的薄膜沸腾传热。此外，超亲水性 GNPs 涂层促进气泡分离过程并抑制沸腾过程中干斑的形成。相反，疏水性和超疏水性 GNPs 涂层充当水插入的不透水毯，并降低流动沸腾率。还研究了过冷度和本体流的质量通量对性能增强的影响。本研究旨在研究归因于石墨烯功能化涂层的流动沸腾增强，并提供有关石墨烯超快水渗透机制进入过冷流动沸腾传热的有趣见解。