Modeling of Heat and Mass Transport in Two-Phase Media by Considering Liquid Pressure

A new model to describe heat and mass transport during drying of two-phase media is proposed. The medium is considered as a two continuous immiscible phases on which the method of volume averaging is applied in order to derive continuum equations for multiphase systems. The liquid flow is induced by a pressure gradient which cannot be deduced from the capillary pressure like in a triphasic medium. Numerous authors avoid this problem by introducing a phenomenological law binding the pressure to the volume fraction of the liquid phase. In the obtained model, the pressure is calculated from the solid mass conservation in such a way that transport phenomena depend notably on the rheological behavior.