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The article presents the results of experimental studies of the air heating efficiency in heliocollectors with different surface forms developed in order to justify their use in equipment for active ventilation of grain and feed raw materials.

The article deals with the study of the separation of grain materials in pneumatic channels with an artificially formed distribution of air velocity in the cross-section of the channel, to determine the rational form and parameters of the material supply

The possibilities of the action of uneven air flows on the grain material in the separating channels are still not used enough. The reason for this is the insufficient knowledge of the processes of interaction of the components of the grain material with an uneven air flow. The purpose of the research is to increase the efficiency of grain material separation according to aerodynamic properties by purposefully changing the diagram of air velocities in the channel sections using the actions of lateral and aerodynamic forces. The separation efficiency of grain material components was determined by trajectory analysis. The different geometry of the pneumatic separation channel was studied. The study of the distribution of air velocity and air pressure vectors in a vertical annular channel was carried out using the FlowVision software. It has been established that a change in the air velocity diagram can be implemented both by changing the geometric parameters of the channel and by additional distributed air supply through the perforation in the side walls of the pneumatic channel. Based on the analysis of the velocity field, an improved scheme of a pneumatic gravitational separator is proposed for separating grain material into three fractions according to aerodynamic characteristics.

The article considers the issue of increasing the efficiency of coolers of the material heated during drying by using a heat pump unit to produce artificial cold. The scheme of use of a thermal pump in a complex with the drying installation and the portable cooler of material is offered. A mathematical description of the stationary modes of operation of the drying unit, material cooler and heat pump elements on the basis of a steam compressor refrigeration unit is formulated. At creation of physical and mathematical models of heat and mass transfer in the course of drying and cooling of material (grain) the following conditions are accepted simplifying the mathematical description, but without changing real process: moisture from the material is removed according to Dalton's evaporation law, while the moisture in the material evaporates and is removed simultaneously; moisture content and temperature in the volume of the material are evenly distributed, heat and mass transfer occurs only between the surface of the material and the drying agent; the effects of radiation and contact heat transfer are taken into account by heat transfer coefficients; stationary fields of temperature and moisture content are assumed to be one-dimensional, which vary according to the coordinate calculated in the direction of movement of the material; when cooling the moisture removal material is not taken into account for low residual moisture; the size of the surface of the material in the process of drying and cooling does not change; the heat exchange equipment of the heat pump is an object with concentrated parameters. Using the obtained mathematical dependences, graphical dependences of changes in grain and air temperature are constructed, which allow to evaluate the expediency of using a heat pump. The formulated mathematical model of stationary modes of the heat pump drying unit with artificial cooling of the dried material can be used to evaluate the feasibility and energy efficiency of the used refrigeration machines for grain cooling, especially after high-temperature processing. The obtained analytical dependences in the form of a closed system of equations can be used to optimize the parameters of the heat pump drying unit by the criterion of minimizing energy consumption.