MATHEMATICAL MODELING OF COMBINED IR AND MICROWAVE DRYING OF PLANT RAW MATERIALS UNDER VACUUM CONDITIONS

In the context of the development of the agro-industrial complex (AIC) of the Russian Federation, the production of fruit and vegetable products is of particular importance. They are characterized by a high moisture content and a short shelf life, therefore they require the creation of special conditions for the preservation of vitamins and other valuable biological substances, for example, by drying. Since the drying process can be multi-stage, it is necessary to use effective technological approaches to control the drying mode, and this concerns the automation of all elements, as well as a combination of exposure to various physical fields on the dried material. A drying unit operating in automatic mode was considered. Thermal analysis and recording of the heater power using a multimeter were carried out. The study of the temperature field distribution on the heater surface in the heat emission mode was carried out by a contactless method using a thermal imager. The article presents a mathematical model of a system for processing fruit and vegetable products, which includes such technological operations as microwave and vacuum drying. For the effective operation of the unit, a control system was used that provides full automation of drying. The presented mathematical model makes it possible to find the dependence of drying time on power, which allows for efficient distribution of the power of drying systems at different stages. Drying of plant materials (pumpkins to 20% humidity and then reducing humidity to 5-12% using microwaves) is efficient.