Dimensionless modeling for convective drying of tuberous crop (Solanum tuberosum) by considering shrinkage

摘要

The shrinkage of biological materials (agri-food), is a common phenomenon developed during a drying operation that directly affects the product quality. In this work a dimensionless mathematical model including the reduction at the interface of a high moisture content food (tuber) in 1D geometry was developed. The mass and heat conservation equations coupled to the Leibniz-Reynolds Transport Theorem (LRIT) at the interface of a high moisture content food were solved. The system of nonlinear unsteady state equations was solved by using a multi-frontal massively parallel sparse direct Solver. In order to validate this model, tuberous crop slices were dried at three temperatures: 40, 50 and 60 degrees C, relative humidity of 25% and a constant airflow of 1.5 mks. Drying kinetics and the evolution of temperature within the product were logged. The model is able to simulate the moisture loss and predict the highest thickness change. The simulations show a good agreement with the experimental drying kinetics, as well as for the evolution of temperature. Simulations show 1-D shrinkage is not linear and the model improves its prediction when the drying temperature is higher (intensive mass flux). (C) 2017 Elsevier Ltd. All rights reserved.