ABSTRACT
Drying is a simultaneous heat and mass transfer problem involving multiphase species. Unlike the single-phase model, the multiphase model considers the migration of water with its liquid and gaseous phase. In multiphase modelling, individual equations are required to calculate the conversion of solid, liquid, and gas species. This chapter discusses the additional concepts that are important in developing multiphase modelling. In a multiphase problem, the total vapour flux on the surface encompasses evaporation from liquid water and existing vapour on the surface. The chapter also discusses the energy and mass conservation equation. Details of the equations related to porous media can be obtained in the pioneering work of Whitaker and Bear. The chapter presents and discusses the profiles of moisture, temperature, and evaporation rate. The deformable nature of porous materials and physicochemical properties are the main challenges that are encountered in the development of multiphase modelling.
