COMPARATIVE EVALUATION OF THE STRUCTURAL DESIGN OF MICROWAVE CONVECTIVE HOP DRYERS

Abstract

In hop production, the main scientific problem is the low energy efficiency of hop dryers with convective heat supply and the absence of small-sized mobile continuous-flow hop dryers for farms that ensure the preservation of the consumer properties of hops at reduced operating costs. In order to reduce the operating costs of drying hops, work is being carried out aimed at clarifying the drying modes that contribute to the best preservation of consumer characteristics, and the improvement of technologies and technical means that would reduce operating costs. A new method of drying hops by ultra-high-frequency energy supply deserves attention. (Research purpose) The research purpose is revealing the effectiveness of an ultrahigh-frequency convective hop dryer of continuous-flow action by evaluating the developed structural designs of hop dryers with metal-dielectric resonators that ensure uniform drying and disinfection of freshly harvested hops and electromagnetic safety without a shielding housing at reduced operating costs in the conditions of hop farms. (Materials and methods) Carried out three-dimensional modeling of the structural designs of hop dryers in the Compass 20 program, determined the electrodynamic parameters of the ”generator-resonator“ system in CST Microwave Studio. (Results and discussion) Solved the problem of optimizing the structural design and dimensions of metal-electric resonators. It was shown that the main criteria are the correctly agreed parameters of the electrodynamic system ”generator-resonator“: the intrinsic Q-factor of the resonator, the voltage of the electric field, its uniformity of distribution, the power of the radiation flux, the volume of the resonator. The electro-dynamic parameters of 11 hop dryers with different designs of resonators were analyzed: hemispherical, semi-cylindrical, cylindrical, toroidal, prismatic, ellipsoid and others. (Conclusions) It was found that toroidal and hemispherical resonators have a maximum intrinsic Q-factor of up to 8000. It was determined during the evaluation of deviations from the average value of the intervals of variation of the criteria that hop dryers with resonators in the form of a paraboloid and hyperboloid, and semi-cylindrical, are effective.