ROLE OF NANOCONFINEMENT ON THIN FILM EVAPORATION

Thin film boiling and evaporation have been recognized as most efficient thermal management solutions for reliable operations of high power density electronics. Liquid-vapor phase change process plays an important role in many natural phenomena and industrial applications ranging from thermal management of electronics, power generation, water harvesting, and water desalination. Enhancing liquid-vapor phase change efficiency push the boundaries specially in electronic industry. To achieve this purpose, many efforts have been devoted for better understanding of the underlying mechanism and improving performance solutions. Recent progress in micro/nano fabrication techniques have opened an avenue for scientists and engineers to elevate thermal conversion and management by manipulating effective parameters. Herein, we aim to survey the most enlightening recent advances in developing various nanoengineered architectures for thin film evaporation enhancement including micropillars and nanowires, micro/nano porous membranes, hierarchical structures, and micro/nano channels. We study their functionalities and compare their efficiencies. In the next step, we focused on the role of planar nanoporous membranes in thermal management due to their high heat removal potential. We utilized anodic aluminum oxide (AAO) membranes and a high heat flux of 560 W/cm2 is achieved with wall superheat of ~ 60 ℃. Thin film boiling as the next stage of pool boiling dramatically increases the bubble departure frequency as a result of reduced conduction resistance in liquid microlayer. As boiling regime enters the thin film region, the bubble diameter significantly shrinkages promoting the departure process. Moreover, separate liquid-vapor pathways play a critical role by providing liquid to nucleation sites in a more efficient way. This work suggests utilizing thin film boiling as an advanced strategy for promoting heat removal performance in high power electronics.