Moisture Transport in Unconsolidated Porous Media During Drying

本项目对颗粒状多孔介质干燥过程中的水分输送过程进行了实验研究。原则上，其机制很简单——水蒸气在气相中由于分压梯度而扩散，而在液相中由于毛细力而对流。最近的可视化研究清楚地表明，局部非均质性的影响主要受两个参数的影响：键数（表面张力效应与重力效应的比值）和粒径分布的方差。为了探索更大范围的邦德数，研究者将使用100到1000微米的玻璃球填充床。将使用球形颗粒和破碎玻璃颗粒的混合物来探索粒径分布差异的影响。

This project involves an experimental study of the moisture transport process that occurs during the drying of granular porous media. In principle, the mechanisms are quite simple--diffusion of water vapor in the gas phase owing to gradients in the partial pressure and convection in the liquid phase owing to capillary forces. Recent visual studies have clearly indicated that the influence of local heterogeneities is dominated by two parameters: the Bond number (ratio of surface tension effects to gravitiational effects) and the variance of the particle size distribution. To explore a wide range of Bond numbers, the investigator will use packed beds of glass spheres ranging from 100 to 1000 microns. The influence of the variance of the particle size distribution will be explored using mixtures of spherical particles and mixtures of crushed glass particles.