Modeling of multiphase flow with phase change in porous media - a case study

A general numerical model developed to simulate the time-dependent changes of moisture content, temperature and pore pressures is proposed for a porous material. The model is based on a coupled heat and mass transfer mathematical formulation. The model's validation is conducted using experimental data for concrete. The gravimetric technique is used to obtain the experimental data on moisture content in cylinders made up of fully saturated concrete exposed to drying. Further to demonstrate the applicability of the model, it is also studied the moisture migration, temperature development and thermal stresses in a concrete element exposed to fire. The obtained results indicate that during fire, several degradation phenomena are taking place at the same time. Thermal stresses developed by the temperature differential, especially when temperature-dependent material properties are taken into the account, along with the increase of pore pressures, may contribute to structural failure.