Modeling of Nanoporous Membranes for High Flux Thin Film Evaporation
Thin film evaporation promises high heat flux thermal management solutions for next generation high performance . In particular, we are investigating this approach that takes advantage of a nanoporous membrane. However, fundamental understanding of heat and mass transfer during evaporation at the liquid-vapor interface confined within the nanopores is essential to realize such a concept. In this work, we developed a detailed computational model that captures evaporation from cylindrical nanopores where the meniscus is pinned at the top of nanopores. We solved the laminar flow and heat transfer problem in the liquid phase using finite methods, established a second-order differential equation to determine the meniscus shape and investigated vapor transport incorporating the recondensation inside the pore and the non-equilibrium effect due to the bulk vapor flow. We obtained the interfacial heat flux and heat transfer coefficient which are functions of both the local temperature and the liquid pressure at the bottom of the pore. This work sheds light on the complex physics of thin film evaporation in nanoporous membranes, which facilitates the design of high flux thermal management devices.