Air Impingement Drying of Foods: Modelling Coupled Heat and Mass Transfer and Experimental Validation

Abstract

A numerical model was developed to predict heat and mass transfers within the product and the boundaries conditions of temperature and airflow around the product during the drying of infinite slabs. Variable thermophysical and hygric properties during the drying were also included in the model. Effective moisture diffusivity was a function of the temperature. Convective coefficient was estimated by a direct measurement using a fluxmeter. A system of non-linear unsteady-state partial differential equations were solved by using finite elements methods. Air impingement drying of a gel made of carboxymethylcellulose (CMC) to simulate water-rich foods from 40 °C to 70 °C and from 1 m s-1 to 17 m s-1 was studied. Predicted results were found fairly well in line with the experimental ones (