Agricultural ecology offers new methods and approaches to the implementation of production processes that will reduce the harmful effects on the environment. The article describes approaches to the formation of a combined calculation scheme of the process of grain materials fractionation by air flow in a horizontal channel. The main idea of the method is a consistent clarification of the mutual influence of grain and air flows in the calculation of the field of air velocities and trajectories of dispersed particles. The mathematical model of air flow motion is based on the finite element solution of the Laplace equations for a plane potential flow with variable porosity. Differential equations of motion of dispersed particles were solved numerically, using the method of average acceleration, with iterations at each step and taking into account the distribution of the air velocity field in the channel.The combined calculation scheme is constructed from several iterations with a step-by-step approach to the simulated process of pneumoseparation. At the first stage, the finite element model of the air flow is constructed without taking into account the influence of the flow of grain material. In the second stage the differential equation of grain material particles motion are solved. According to the solutions of these equations, the zone of greater or lesser porosity is determined. The next step is to recalculate the air flow rates in the channel taking into account the porosity of the various finite elements. The result of solving the differential equations of motion of dispersed particles varies depending on the air flow velocities. Thus there is a consistent approach to the description of the process of interaction of grain and air flow.According to the proposed algorithm the computer program in C# language has been developed. It provides the ability to graphically and numerically control the results of the calculation. The program interface contains three screens with tabular data and layout of finite elements, which, after calculations, is applied to the vector of air flow velocity and trajectories of particles with desired aerodynamic properties. Examples of calculation are presented. According to their results, a change in the value and distribution of air flow velocities at the inlet to the channel is proposed, the positions of the fraction receivers in the lower part of the horizontal pneumatic separation channel are determined.
ISSN 1995-4301
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