How ions distribute in a drying porous medium: A simple model
How ions distribute in a drying porous medium: A simple model
复制标题
DOI：
10.1063/1.1451081
复制
发表时间：
2002-04-01
影响因子：
4.6
通讯作者：
Michels, MAJ
中科院分区：
文献类型：
--
作者：
Huinink, HP;Pel, L;Michels, MAJ
地表盐结晶对建筑物和纪念碑来说是一个重要的问题。我们不考虑盐晶体的形成，而是关注离子在干燥多孔介质中的输运性质。我们处理干燥过程的第一阶段，水仍然均匀分布在整个介质中。提出了一个近似的模型，同时考虑了对流和扩散。结果表明，关键参数为蒸发表面的Peclet数，Peequivalent tohL/epsilon，其中h、L、epsilon和D分别为干燥速率、样品尺寸、孔隙率和扩散常数。当Pe1（对流大于扩散）。发现了Peapproximate to1的交叉行为。因此，第一批晶体很可能在Pe材料的本体和界面处形成
Salt crystallization at surfaces is an important problem for buildings and monuments. We do not consider the formation of salt crystals as such, but focus on transport properties of ions in a drying porous medium. We deal with the first phase of the drying process, where the water is still uniformly distributed throughout the medium. An approximate model is presented, which accounts for both convection and diffusion. It is shown that the key parameter is the Peclet number at the evaporating surface, Peequivalent tohL/epsilonD, where h, L, epsilon, and D are the drying rate, sample size, porosity, and diffusion constant, respectively. When Pe1 (convection dominates over diffusion). Crossover behavior is found for Peapproximate to1. Therefore, it is likely that the first crystals will be formed both in the bulk and at the interfaces of the material when Pe