Investigation of kinetics of thin layer drying of fruits using computational fluid dynamics

Abstract

The roles of temperature and velocity of air and the limits of their influence in thin layer drying of fruits were studied using computational fluid dynamics code - ANSYS FLUENT 18. Unripe banana (Musa cavendishii) was used as sample and mass transport from the fruit to the drying air was simulated by solving specie transport equation without reaction. Velocity helped to regulate the concentration gradient between the chamber space and the fruits surface as it was responsible for the transportation of free H2O molecules at the surface of the fruit to the environment. Temperature on the other hand was the major determinant of the rate at which species were transported from the fruit to the drying air and it is defined by mass diffusivity. The computed values of effective diffusivity at the test temperatures ranged between 1.62E-10-3.85E-10. However, these values dropped slightly when shrinkage effect was factored in.