Theoretical background for combination of sieves of combine harvester cleaning system

The study was carried out in order to substantiate the development of a combination of sieves for the cleaning system of a combine harvester. The research is based on the general-logical method and mathematical analysis. It is shown that in the process of separation of a grain heap in the cleaning system of a combine harvester, the effect of an air flow on a given material flow is formed. In the course of the study, analytical dependences are obtained that characterize the change in the displacement of the grain heap layer on the cleaning sieve of the combine harvester in both horizontal and vertical directions relative to the sieve from the speed of the air flow. The relationship between the height of the grain heap layer on the sieve and the air flow rate, as well as between the delivery of the grain heap to the sieve and the air flow rate of the combine harvester cleaning system is disclosed. The systems of equations are shown up that characterize the change in the height of the grain heap layer on the sieve depending on the sieve type and the air flow rate of the combine harvester cleaning system. Graphical interpretation of the obtained regularities which reveal the nature of the change in the height of the grain heap layer on the sieve depending on its type and air flow rate, is presented.