Wang Shenwei, Zhou Hongwei, Sun Zhiwei, Xu Shenghua, Ouyang Wenze, Wang Linwei
Key laboratory of Microgravity (National Microgravity laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China.
School of Engineering Science, University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2020 Jun 3;10(1):9084. doi: 10.1038/s41598-020-65879-0.
We investigated the evolution of concentration and phase structure of colloidal suspensions in a two-ends-open tube during drying process. The volume fraction and crystal structure of suspension in the capillary tube were determined by reflection spectrometer during drying process. Our experimental results show: (a) evaporation takes place in two directions of the tube, though much stronger in one direction than the other; (b) during drying process, colloidal suspension column along the tube can be divided into four regions, namely, the close packed region, concentrated region, initial concentration region and dilution region. A new model describing the evolution of concentration profile was proposed and the calculated results based on the model are in good agreement with the experimental ones. According to solute conservation, we also present a simple way to estimate the concentration of close packed region.
我们研究了两端开口管中胶体悬浮液在干燥过程中浓度和相结构的演变。在干燥过程中，通过反射光谱仪测定毛细管中悬浮液的体积分数和晶体结构。我们的实验结果表明：（a）蒸发在管的两个方向上发生，尽管在一个方向上比另一个方向强烈得多；（b）在干燥过程中，沿管的胶体悬浮液柱可分为四个区域，即密堆积区域、浓缩区域、初始浓度区域和稀释区域。提出了一个描述浓度分布演变的新模型，基于该模型的计算结果与实验结果吻合良好。根据溶质守恒，我们还提出了一种简单的方法来估算密堆积区域的浓度。
