Modelling convective drying of foods: A multiphase porous media model considering heat of sorption

Abstract

This study presents a theoretical and numerical analysis to derive a multiphase model of heat and mass transfer for low intensity/temperature convective drying of hygroscopic porous materials, with focus on food products. Some commonly used simplifications in modelling drying and similar processes are evaluated and a reduced model is obtained consequently. Such model is close in complexity to single-phase or diffusion-based models, but presents a multiphase and multiphysics nature, which is important to understand the underlying physics of the process. In addition, this multiphase model considers the heat of sorption in order to account for energy aspect of bound water transport, an essential feature for dealing with hygroscopic materials. The proposed formulation was implemented in commercial software to contribute to the developing of more user-friendly modelling tools. Finally, the model is used to discuss some relevant aspects of multiphase transport modelling such as treatment of evaporation rate term or closure of system of equations.