Robinson Joshua F, Gregson Florence K A, Miles Rachael E H, Reid Jonathan P, Royall C Patrick
H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom.
School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, United Kingdom.
J Chem Phys. 2020 Feb 21;152(7):074503. doi: 10.1063/1.5139106.
A quantitative understanding of the evaporative drying kinetics and nucleation rates of aqueous based aerosol droplets is important for a wide range of applications, from atmospheric aerosols to industrial processes such as spray drying. Here, we introduce a numerical model for interpreting measurements of the evaporation rate and phase change of drying free droplets made using a single particle approach. We explore the evaporation of aqueous sodium chloride and sodium nitrate solution droplets. Although the chloride salt is observed to reproducibly crystallize at all drying rates, the nitrate salt solution can lose virtually all of its water content without crystallizing. The latter phenomenon has implications for our understanding of the competition between the drying rate and nucleation kinetics in these two systems. The nucleation model is used in combination with the measurements of crystallization events to infer nucleation rates at varying equilibrium state points, showing that classical nucleation theory provides a good description of the crystallization of the chloride salt but not the nitrate salt solution droplets. The reasons for this difference are considered.
从大气气溶胶到喷雾干燥等工业过程，对水性气溶胶液滴的蒸发干燥动力学和成核速率进行定量理解对于广泛的应用都很重要。在此，我们引入一个数值模型，用于解释采用单颗粒方法对干燥自由液滴的蒸发速率和相变进行的测量。我们研究了氯化钠和硝酸钠水溶液液滴的蒸发情况。尽管观察到氯化物盐在所有干燥速率下都会重复结晶，但硝酸盐溶液实际上可以在不结晶的情况下失去几乎所有水分。后一种现象对于我们理解这两个系统中干燥速率和成核动力学之间的竞争具有启示意义。成核模型与结晶事件的测量结果相结合，以推断不同平衡状态点下的成核速率，结果表明经典成核理论能很好地描述氯化物盐的结晶情况，但不适用于硝酸盐溶液液滴。我们考虑了这种差异的原因。
