METHOD OF EVALUATING CHANGES IN TEMPERATURE AND MOISTURE CONTENT USING ELECTROMAGNETIC DRYING OF SAMPLE OF ARBITRARY SHAPE

Analytical methods were used to study the process of removing moisture from the sample of arbitrary shape, located in the working chamber of the installation for drying by electromagnetic waves. The sample is blown by the air flow and exposed to two types of radiation, having a large and, accordingly, small compared to the size of the sample penetration depth. To increase the uniformity of blowing and heat treatment, the sample is rotated. The equations of heat and mass transfer theory are used as a mathematical model of drying Lykov in a medium with constant thermal coefficients. Using transformations of three types - averaging over turnaround time, averaging over coordinates, and transition to time asymptotics - the original equations are reduced to a form that contains only numerical characteristics of functions.  On the basis of these relations, formulas for the values called characteristic temperature and moisture content differences, which characterize the degree of heterogeneity of the corresponding fields, are proposed. The introduced differences depend on the thermophysical parameters of the material, the typical size of the sample (for the ball – diameter), as well as on the power of generators of electromagnetic waves with a large and small penetration depth. In the case of a ball, the characteristic differences give the exact values of the temperature difference and the moisture content difference between the surface of the ball and its center. The results of the work allow to organize electromagnetic drying, in which at a high intensity of moisture evaporation from the surface of the sample there is no overheating of the material (due to a large temperature drop) or its destruction from mechanical deformations (due to a large difference in moisture content).