MODELING OF THE DEEP DRYING PROCESS OF GRANULATED POLYAMIDE AT CONVECTIVE-INFRARED ENERGY SUB-SUPPLY

Abstract

On the basis of an analytical solution of the problem describing the drying process of a cylindrical body with a combined heat supply (continuous convective and intermittent infrared), the influence of the temperature mode of heating the body on the drying time and the consumption of electrical energy consumed by an infrared emitter is analyzed. The dynamics of intermittent infrared heating of a cylindrical body was modeled on the basis of an analytical solution of the problem, which takes into account the irregularity of irradiation using a unit Heaviside function and the absorption of electromagnetic energy exponentially, as well as convective heat and mass transfer of the body surface with the environment of constant parameters. The kinetics of body drying has been calculated by analytically solving the problem of moisture diffusion in the material with the third type mass transfer boundary condition provided that phase transformations occur at the surface of the body. An internal mass transfer analysis has been performed with deep drying of granular polymers, on the basis of which the diffusion mechanism of moisture transfer inside the material was substantiated, for which PA-6 polyamide in the form of a cylindrical rod has been chosen. The analysis showed that the drying process of the specified polyamide rod occurs in the intra-diffusion region, characterized by the condition that the moisture content of the rod near its surface immediately after the process starts takes an equilibrium value, which was calculated during the analysis of the drying temperature regime. A numerical simulation of the interconnected process of drying and heating a cylindrical rod of polyamide PA-6 under conditions of a combined convective-infrared power supply was conducted, on the basis of which conclusions were made about the choice of the temperature mode of the process.