The theoretical rationale for the use of contact heating when drying seeds in a vacuum

Abstract

Purpose. The rationale for heating seeds by contact in a vacuum by analyzing the solutions of the differential equation of unsteady heat conduction. Methods. The differential heat equation, the Fourier method, the Sturm-Livull problem and the Dirac δ-function are used. Results. Based on the Fourier method and the Sturm-Livull problem, a differential heat equation is obtained, which makes it possible to determine the kinetics of seed heating depending on the thickness of the layer at a known temperature of the heating surface. A graphical analysis of the solution of the differential heat equation showed that for uniform drying of the seeds in vacuum it is necessary to apply mixing during drying. Conclusions. The analysis of the contact heating technological process, which was carried out on the basis of solving the differential equation of unsteady heat conduction, showed that the heating rate of seeds nonlinearly decreases with increasing layer thickness. This leads to uneven drying of the seeds in a vacuum. Therefore, the use of only one contact surface for heating seeds in a vacuum is impractical. Keywords: seeds, contact heating, heating temperature, layer thickness, vacuum, drying, heating.