Search

One of the main requirements for grain dryers is the need for high-quality cooling of grain material after drying. Today, the most widespread are grain coolers built into grain dryers. As the practice of operation has shown, the most widespread in agriculture mine grain dryers with their cooling zones are ineffective: the temperature of the grain after cooling often exceeds the ambient air temperature by 15-30 0C, which is unacceptable. Devices with boxes have such disadvantages as uneven distribution air in the volume of grain mass and the corresponding uneven temperature field of the cooling air, limited opportunities for intensifying heat transfer during grain cooling. More promising for agricultural grain dryers are external coolers, which are installed separately from the dryer and can operate in an independent mode, which has a number of advantages: the quality of cooling improves, the productivity of existing grain dryers increases due to the use of the cooling part as a dryer. The main disadvantages of using the existing external column coolers: the need for an additional vehicle - a bucket elevator for reloading grain from the dryer to the column; vertical arrangement, it is necessary to use transporting means for grain for feeding to a considerable height. But if a pneumatic transport loader with a pulsating air flow is used as a vehicle, then the efficiency of the coolers can be increased due to the removal of a part of the heat accumulated by the grain by the transporting air flow. The paper proposes an analytical rationale for increasing the efficiency of coolers with pneumatic transport in a pulsating air flow.

The article presents field research results on the effectiveness of different moisture and nutrition conditions at the cultivation of early potato under drip irrigation in southern Ukraine. The scheme of the experiment included the treatment with the complex Mochevyn K as an additional control and different methods and correlation of fertilizers Plantafol (treatment of tubers before planting, fertilizing, at budding and their combination), as well as different soil moisture conditions (irrigation rates of 100 and 200 m?/ha). Studies have shown that the average yield of early potato without irrigation was 10.44 t/ha. Moisture conditions significantly affected the yield of young tubers - irrigation at a rate of 200 m?/ha provided 21.61 t/ha, whereas reducing the irrigation rate to 100 m?/ha led to a decrease in yield - 19.86 t/ha. The first treatment of planting tubers, treatment of plants at sprouting and during budding provided almost the same yield. The second and the third treatments of plants and tubers did not lead to a significant increase in yield. The highest productivity of potato was provided by Plantafol treatment of tubers and combination of tuber treatment with foliar feeding at mass sprouting phase with a 200 m?/ha irrigation rate for two years: 24.16 and 23.22 t/ha.

Development of a mathematical model and calculated analytical dependencies for determining the trajectories and parameters of grain movement in a vibro-fluidized layer of grain material components under the action of a pulsating air flow. They are based on the methods of deterministic mathematical modeling and theoretical mechanics based on the equations of motion of a material point at a variable air flow speed and the action of a pulsating air flow. Theoretical studies were carried out using the methods of mathematical analysis and modeling. The research results were processed using elements of the theory of probability and mathematical statistics using software packages; to determine the rational parameters of the process, the method of statistical experiment planning was used. A mathematical description of the motion of the grain material particles in a combined vibration-air separator under the action of a pulsating air flow of variable speed is given. The trajectories of motion of particles with different sizes are obtained. The obtained equation of motion of a particle under the influence of a pulsating air flow makes it possible to determine the dependence of the speed of movement of the material in a vibro-fluidized layer of grain material on a number of factors: the geometric parameters of the sieve-free sieve, the feed angle of the material, the initial kinematic mode of the material, the index of the kinematic mode of the sieve-free sieve, as well as the coefficient of windage of the grain. On the basis of theoretical studies, the possibility of separating particles of grain material into fractions according to aerodynamic properties with vibropneumatic loading of grain into the channel has been determined. The use of a pulsating air flow as a separating carrier, and taking into account the deflecting forces, made it possible to significantly increase the splitting of the trajectories and the criterion for dividing the grain into fractions.

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.