Heat and mass transfer during convective drying of thin flat wet materials

The method of calculating convective drying of light industry thin materials based on the A. V. Lykov’s equation of drying kinetics and the B. S. Sazhin’s calculating method of drying is described. Processing of experimental data on wool felt drying, natural leather drying and fabrics drying is presented. Equations for determining the densities of heat flows, the intensity of moisture evaporation, the duration of drying process, and the temperature for the period of falling velocity are given. The values of the heat transfer coefficient and the Bio number for the second drying period are calculated. It was found that under mild drying conditions and insignificant temperature gradients along the thin body cross-section, the Bio number takes values less than one, and the main limiting factor for drying thin materials is the external heat and humidity exchange of the evaporation surface with the environment. It is shown that the relative drying speed is determined only by the moisture content of the material and does not depend on the drying mode. The comparison of the calculated parameters of drying according to the given formulas with the experimental values is given. The mismatch of values is in the acceptable accuracy zone of the experiment.