Comparison of Stefan model with Single-phase model of water infiltration process in unsaturated porous media (theory and experiment)

Stefan models have been used for many problems such as freezing and melting processes. However, there are few research reports on using Stefan model for the problem of unsaturated flow in a granular packed bed, but the Stefan model has never been used before for considering the effects of particle sizes and supplied water flux to water saturation and moving infiltration fronts. The purpose of this work is to present novel mathematical models and numerical schemes for solving one-dimensional infiltration flow problems. A systematic development and comparison of two proposed models (Single-phase model and Stefan model) is performed. The influences of particle sizes and supplied water flux on water infiltration, i.e., the infiltration layer are studied in detail. It is found that the results of the comparison between these two models are in good agreement. Furthermore, the Stefan model shows better agreement with the experimental results than the Single-phase model. This study shows that the Stefan model can be used effectively for many physical phenomena involving flow infiltration coupled with a moving boundary, compared with other conventional models, i.e., the Single-phase model.