Unraveling the fundamentals of transport across the vapor-liquid interface

Unraveling the fundamentals of transport across the vapor-liquid interface

Transport of energy and particles across vapor-liquid interfaces is central for growth of rain drops in the atmosphere, evaporation from lakes, distillation columns, development of micro/nano-fluidic devices and much more. The objective of InterLab is to develop theory and methods to reproduce evaporation rates from steady-state experiments with water and octane within an accuracy of 10%. Such a theory is needed urgently since the established alternatives overpredict evaporation rates of water by 2-3 orders of magnitude. The core component of this new theory is the local thermal conductivity in the interfacial region. To reach its objectives, InterLab must fill major knowledge gaps in the fundamental understanding of transport across vapor-liquid interfaces. The tensorial behavior of the local thermal conductivity at the interface will be described and the nature of the thermal insulation layer at the vapor-side of the vapor-liquid interface will be understood. Octane and water will be investigated to clarify the role of hydrocarbon chain contributions and hydrogen bonds. The predictions from the new theory will be tested against nonequilibrium molecular dynamics simulations and new evaporation experiments. To be able to distinguish the different transport mechanisms for evaporation and validate the theory, two experimental rigs will be built. The rigs will measure the pressure to an accuracy that is one order of magnitude better than what has been reported in the literature. A computational fluid dynamics model will be used to extract information about the local heat flux across the vapor-liquid interface to achieve sufficiently high accuracy. The overarching goal is to obtain an understanding, a theory, and quantitative agreement from the molecular level to lab-scale experiments.