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

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 (LRTT) 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 °C, relative humidity of 25% and a constant airflow of 1.5 m/s. 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).