| Drying is a unit operation where water is removed from a material by means of evaporation and mass transfer. It is widely used in industrial manufacturing processes. Many of these processes involve drying of porous materials. Porous media are, in general, heterogeneous systems. The microstructure of the pore space influences transport properties and hence, drying rates. Thus, a quantitative geometrical characterization of the pore space is crucial for accurate prediction of porous media drying rates. Simulation of porous media structure, given a specific size distribution of constituent particles, followed by pore-space characterization is a powerful as well as economical predictive tool for product design. Realistic unconsolidated porous media were reconstructed through Monte Carlo gravitational particle packing simulation. The porous media simulation was validated by comparison with extracted transport related micro-structural parameters from x-ray micro-CT (computed tomographic) images. A mathematical morphology based three-dimensional image processing algorithm was developed to characterize the pore space in the simulated porous media. This realistic pore-throat network information was utilized in an invasion percolation based simulation of porous media drying and showed satisfactory agreement with quantitative data extracted from in-situ NMR (nuclear magnetic resonance) imaging experiments. |
