Study on Laser-Controlled Surface Preparation and Condensation Heat Transfer Characteristics of Copper-Based Micro-Nano Structure Surface

Abstract The micro-nano structure surface has significant influence on the condensation heat transfer. Studying and designing micro-nano structure parameters help to better explore methods for improving surface condensation heat transfer performance. In this paper, we firstly processed hill shaped microstructure with customizable structural parameters on the copper surface using femtosecond laser technology. Subsequently, copper oxide nanowire structures were prepared on copper surfaces with hill shaped microstructures utilizing thermal oxidation method by tube furnace. We have been conducted a series of condensation heat transfer experiments on the copper-based micro-nano structure surface. Further the condensation heat transfer coefficient on the surface of micro-nano structures were analyzed. Additionally, the dynamic behavior of condensation droplets was also investigated. The surface processing results show that the surface structure parameters can be well customized using femtosecond laser technology by adjusting the laser processing parameters and designing patterns. The experimental results of condensation heat transfer indicate that the surface heat transfer coefficient of the copper-based micro-nano structure has been significantly improved compared with smooth copper surface. It has been found that there is droplet jumping phenomenon at low subcooling, while flooding phenomenon occurs at high subcooling.