Moisture Migration in Stored Granular Materials

摘要

Thermally-driven moisture migration during the storage of polycarbonate pellets in a cylindrical silo is investigated in the present work. The bed of pellets is assumed as saturated porous medium with hygroscopic activity at a uniform initial temperature. The side wall of the cylinder undergoes a change to a low temperature while the ends of the packed cylinder are considered to be insulated. A mathematical model for the transient transport of heat and moisture is developed, where the Darcy law is assumed for the flow, the Boussinesq approximation is used for accounting density variations and the adsorption equilibrium of moisture is considered as a linear relationship to the relative humidity.-The dimension analysis of the model and its numerical solution allow for the identification of the mechanisms responsible for moisture migration and for the prediction of moisture maldristibution.