Numerical analysis of convective drying of a moving moist object

Abstract

Convective drying of a moving moist object is investigated numerically solving the conservation equations of mass, momentum, energy and air moisture concentration based on a k–∊ turbulence model in the external region of the object as well as the conservation equations of energy and object moisture concentration in the internal region. The external and internal conservation equations are coupled to the heat and mass transfer conditions on the object surface including the effects of evaporation and water activity. The numerical results show that the analogy between heat and mass transfer for the convective drying is valid only when the object temperature is close to the equilibrium temperature. The simple analytical formulations developed for the total drying rate are found to compare well with the numerical results. The effects of object velocity and thickness and the wall heat flux on the drying rate are quantified.