The article substantiates the necessity of obtaining the dielectric properties of grain materials for studying the processes of microwave convective heat treatment of grain. The shortcomings of the existing methods for studying dielectric properties in the study of a fluidized bed and suspended layer are described. A laboratory installation and an experiment on the investigation of a suspended grain layer are described. The results of experimental studies on the determination of the dielectric loss factor of wheat subjected to microwave treatment are presented. The results obtained for different material densities correspond to the general dynamics, but differ significantly in level. Thus, for a dense layer, which corresponds to a density of 660 kg / m3 in the humidity range of 11-30%, the dielectric loss coefficient varies in the range 0.18-0.42; for the fluidized bed (440 kg / m3) 0.06-0.15; for the weighed (220 kg / m3) 0,1-0,3.
Keywords: energy efficiency, the microwave field, thermal processing of grain, field modeling, direct heating, dielectric
The study combined methods of influence on agricultural inputs in the process of post-harvest handling is largely associated with the development of instrumentation that allows to control the factors that affect the material. The article describes the results of theoretical and experimental studies to determine the electromagnetic field in a layer of grain material undergoing microwave treatment. In the field of theoretical research will come an exponential decay law of an electromagnetic wave in the material and the model built in the software package CST Studio. It is also a view of equipment designed for the experimental evaluation of the field intensity and its distribution pattern in the layer of the processed product. The dependences describing the measurement principle is implemented in this device. It provides an assessment of compliance with the theoretical and experimental methods of measurement. Increasing the accuracy of the experimental measurements can be achieved through the use of optical contact temperature sensors, as well as the use for the manufacture of the receiving materials with known data reliably dielectric properties in a given temperature range. The data obtained can be used for determining structural parameters of the microwave exposure zone, and for the development of control systems equipment. Finally, the conclusions based on the results of the work presented.
Keywords: energy efficiency, the microwave field, thermal processing of grain, field modeling, direct heating, dielectric