CONTINUOUS AND INTERMITTENT DRYING (TEMPERING) OF OBLATE SPHEROIDAL BODIES: MODELING AND SIMULATION

In this work, modeling of continuous and intermittent drying of oblate spheroidal bodies is presented. The model considers the liquid diffusion as the only process of mass transfer inside the body, constant diffusion coefficient and equilibrium conditions at the surface of the solid. The diffusion equation is described in the oblate spheroidal coordinates system, for the two- dimensional case discretized using the finite volume method and fully implicit formulation. Based on the literature, experimental data of the properties and physical dimensions of lentil grains were used in the all simulation. Several processes of intermittent drying for the lentils were simulated: using a same time of tempering (time of rest), beginning in different drying time and for two or more intervals (time steps) along the process. For a same useful time of use of the dryer, it was observed that the intermittent drying always increases the efficiency of the process. Another outstanding result is the improvement of the final quality of the product due to the absence of great moisture content gradients inside of the product during the drying process.