Abstract Evaporation, crystallization and heat transfer in a droplet of NaCl/H2O solution have been studied experimentally. Crystallization began at the edges of the droplet at solution supersaturation S = 1.94 (S = Csup/Csat, where Csup is the salt concentration in a metastable region (supersaturation), and Csat corresponds to saturation), which is noticeably higher than the previously obtained supersaturation for the droplet, microcapillary, and when using surfactant. When the droplet evaporated on the heated wall, the supersaturation of the salt solution was noticeably higher than when evaporating without heating. Four characteristic modes of evaporation and crystallization are distinguished. The ratio of the crystallization rate to the evaporation rate (jcr/jev) may be both substantially greater and less than one. It is shown that the heat transfer and the crystallization rate are regulated by Marangoni convection. The data obtained are of interest for the development of modern concepts of high-temperature crystallization in the presence of intense Marangoni flow.

中文翻译：

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一滴NaCl溶液中不同传热和结晶模式：影响结晶速率和传热系数的关键因素

摘要 实验研究了一滴 NaCl/H2O 溶液中的蒸发、结晶和传热。在溶液过饱和度 S = 1.94（S = Csup/Csat，其中 Csup 是亚稳态区域（过饱和度）中的盐浓度，Csat 对应于饱和度）时，在液滴边缘开始结晶，这明显高于先前获得的液滴、微毛细管和使用表面活性剂时的过饱和度。当液滴在加热壁上蒸发时，盐溶液的过饱和度明显高于不加热蒸发时。蒸发和结晶的四种特征模式是有区别的。结晶速率与蒸发速率的比值(jcr/jev)可以显着大于1也可以小于1。结果表明，传热和结晶速率受 Marangoni 对流调节。获得的数据对于在存在强烈 Marangoni 流的情况下开发现代高温结晶概念很有意义。