Unraveling the fundamentals of transport across the vapor-liquid interface

Introduction

Transport of energy and particles across vapor-liquid interfaces is central for the 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%.

Need for New Theory

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.

Knowledge Gaps

To reach its objectives, InterLab must fill major knowledge gaps in the fundamental understanding of transport across vapor-liquid interfaces. The following aspects will be explored:

1. The tensorial behavior of the local thermal conductivity at the interface.
2. The nature of the thermal insulation layer at the vapor-side of the vapor-liquid interface.
3. The role of hydrocarbon chain contributions and hydrogen bonds in octane and water.

Testing the Theory

The predictions from the new theory will be tested against nonequilibrium molecular dynamics simulations and new evaporation experiments.

Experimental Rigs

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.

Computational Model

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.

Overarching Goal

The overarching goal is to obtain an understanding, a theory, and quantitative agreement from the molecular level to lab-scale experiments.