We investigated the effects of salt crystallization on the dynamics of saline water evaporation in porous media. Water mass loss rates from sand columns supplied with NaCl solutions at three concentrations were monitored under controlled ambient conditions. The formation and evolution of salt crystals over sand surfaces were synchronously imaged optically and thermally. Despite identical experimental and ambient conditions, we observed distinct crystallization dynamics that affected evaporative mass loss rates for similar salt concentrations, highlighting high variability of crystallization and its impact on evaporation. We observed the enhancement of maximum evaporation rates by factors of 3 to 14 under our experimental conditions and attributed this enhancement to the formation and evolution of porous crystalized salts at the surface. Additionally, visible intermittent temperature fluctuations of the salt crust were quantified using thermal imagery attributed to the dynamic processes of crystallization, dissolution and evaporation occurring simultaneously at the surface.

中文翻译：

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量化盐结晶对多孔表面蒸发动力学的影响


我们研究了盐结晶对多孔介质中盐水蒸发动力学的影响。在受控环境条件下监测由三种浓度的 NaCl 溶液供应的砂柱中的水质量损失率。沙子表面盐晶体的形成和演化通过光学和热学同步成像。尽管实验和环境条件相同，但我们观察到不同的结晶动力学影响了相似盐浓度的蒸发质量损失率，突出了结晶的高可变性及其对蒸发的影响。在我们的实验条件下，我们观察到最大蒸发速率提高了 3 到 14 倍，并将这种增强归因于表面多孔结晶盐的形成和演变。此外，使用热图像量化了盐壳的可见间歇性温度波动，该热图像归因于表面同时发生的结晶、溶解和蒸发的动态过程。