Computational fluid dynamics of industrial batch dryers of fruits

An industrial batch-type, tray air dryer constructed for drying of several fruits, was investigated. Momentum, heat and mass transfer regarding both g aseous and solid phases was simulated using computational fluid dynamics. A mathematical model of the dryer for predicting the turbulent, three-dimens ional transfer phenomena inside the industrial batch dryer equipment was de veloped and analyzed. The model consists of the full set of partial differe ntial equations that describe the conservation of mass, momentum and heat i nside the dryer. The standard k-epsilon model was used to describe turbulen ce in addition to the governing conservation equations. The simulated profi les of flow field, temperature and humidity of the air phase revealed a lac k of spatial homogeneity of air conditions above the product. The situation was found to greatly influence the distribution of material moisture conte nt of the dried product for the various stages of drying. The investigation was carried out for the representative case of sultana raisins. Copyright (C) 1999 by Marcel Dekker, Inc.