Investigation of the process of pneumatic vibration separation of grain by density during one-dimensional movement of grain flow

Abstract

Annotation Purpose. Formation of a mathematical description of the process of moving grains with different density in vibro-pneumatic liquefied grain medium under the action of pulsating air flow to determine the parameters of movement and the possibility of their separation into fractions. Methods. Theoretical determination of the dependences of the motion of grains with different densities in a vibro-pneumatic grain medium with pulsating air flow determines the mathematical method of research based on the addition and numerical solution of the equations of grain motion in a pneumatic vibrating separator. The mathematical model is formed as a result of drawing up the scheme of force interaction on grain in the vibro-pneumatic liquefied grain environment and the differential equations of movement of grains which are presented by a material point and indicators characterizing physical and mechanical properties of grain environment are received. Results. The motion of the center of mass of grains is considered as the motion of a certain particle, the coordinates of which coincide with the coordinates of the moving coordinate system (x, y), and the mass of a single grain m differs from the grains of the medium in density. The change of air flow velocity and the influence of pulsating air flow on the flow of grain material moving on a vibrating perforated surface are determined. The discrete-periodic change of the flow velocity, which is fed through the perforated support surface into the layer of grain material, is analytically described. The parameters of the grain motion process in an oscillating fluidized medium are determined, which are determined by the solution of a complex system of differential equations using computational methods using a PC. Conclusions. As a result of theoretical research, the possibility of increasing the efficiency of separation of grain materials by specific gravity of grains, by intensifying the process of separation of grain material provided the use of pulsating air flows to separate mixtures on vibrating surfaces and compared with existing separators using horizontal and inclined decks grain separation efficiency material increases by 35–42%. Keywords: pulsating air flow, grain, density, trajectory, fluidized medium, separation process, harmonic law of motion.