Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
Sci Rep. 2017 Jul 10;7(1):5001. doi: 10.1038/s41598-017-05160-z.
For well over one century, the Hertz-Knudsen equation has established the relationship between thermal - mass transfer coefficients through a liquid - vapour interface and evaporation rate. These coefficients, however, have been often separately estimated for one-component equilibrium systems and their simultaneous influences on evaporation rate of fuel droplets in multicomponent systems have yet to be investigated at the atomic level. Here we first apply atomistic simulation techniques and quantum/statistical mechanics methods to understand how thermal and mass evaporation effects are controlled kinetically/thermodynamically. We then present a new development of a hybrid method of quantum transition state theory/improved kinetic gas theory, for multicomponent hydrocarbon systems to investigate how concerted-distinct conformational changes of hydrocarbons at the interface affect the evaporation rate. The results of this work provide an important physical concept in fundamental understanding of atomistic pathways in topological interface transitions of chain molecules, resolving an open problem in kinetics of fuel droplets evaporation.
一个多世纪以来，赫兹-克努森方程通过液体-蒸气界面建立了热质传递系数与蒸发速率之间的关系。然而，这些系数通常是针对单一组分平衡系统分别估算的，它们对多组分系统中燃料液滴蒸发速率的同时影响尚未在原子水平上进行研究。在这里，我们首先应用原子模拟技术和量子/统计力学方法来理解热质蒸发效应如何在动力学/热力学上受到控制。然后，我们提出了一种量子过渡态理论/改进的动力学气体理论的混合方法的新发展，用于研究多组分碳氢化合物系统中碳氢化合物在界面上协同-独特构象变化如何影响蒸发速率。这项工作的结果提供了一个重要的物理概念，有助于深入了解链状分子拓扑界面跃迁中的原子途径，解决了燃料液滴蒸发动力学中的一个悬而未决的问题。
