THE USE OF INFRARED HEATING IN SOIL DISINFECTION IN PROTECTED GROUND AND THE MECHANISM OF HEAT PROPAGATION

Abstract

To disinfect the soil in protected ground, installations operating on various methods of energy supply are used. The article proposes using infrared heating as an energy carrier. When infrared radiation interacts with the surface of the medium, it is partially reflected, and partially penetrates into the material, is absorbed in it and turns into heat. The transfer of thermal energy (kinetic energy of microparticles) in a substance (in a solid layer of soil) is determined by the processes of thermal conductivity. The phenomenon of thermal conductivity is manifested by direct contact of individual particles in the soil layer having different temperatures, through the propagation of elastic waves. Infrared radiation has a small penetrating power. The question arises whether infrared heating can provide the required depth of soil disinfection. Therefore, a theoretical and experimental justification of the heat propagation in the soil is necessary. (Research purpose) The research purpose is studying the possibility of using infrared heating during soil disinfection in protected ground and the mechanism of heat propagation. (Materials and methods) The following assumptions were used for the analytical analysis of soil heating: the soil is isotropic and homogeneous, that is, its properties are the same in all directions, and the temperature dependences of the physical coefficients are weak; the source of heat is the soil surface and it does not depend on temperature. The article presents the solution of the equation of thermal conductivity. (Results and discussion) In order to verify the adequacy of the mathematical model and evaluate the empirical coefficients, full-scale studies of the temperature field in protected ground conditions were carried out. A numerical study of the solution of the equation in the range of its approximations from 100 to 200 terms gives the value of the heating time τ = 15-16 minutes. (Conclusions) It is recommended to use infrared heating when disinfecting only thin layers, for example, a layer of soil on a conveyor belt or any surface in protected soil.