Abstract:In order to reduce the cost and difficulty of manufacturing, and increase the degree of dispersion of sieve particles on the maize air-and-screen metal sieve, a new polyurethane rubber sieve was used to replace the metal sieve, the density of polyurethane rubber and the physical parameter between particles on the sieve and the polyurethane rubber were obtained through experiment, including coefficient of static friction and coefficient of restitution, the shear modulus of the polyurethane rubber was deduced. EDEM was used to establish models of particles on the sieve. The number of particles on different regions of the polyurethane rubber sieve was analyzed through computational fluid dynamics and discrete element method. The simulation results showed that the dispersion of the particles on the polyurethane rubber sieve was greater than that of the metal sieve at the same range of time, which proved that polyurethane rubber sieve was more conducive to particles dispersion which improved the efficiency of sieve. The tests were performed based on the experimental system to verify whether the urethane rubber sieve was met the operational requirements. The loss rate of maize of cleaning device was 1.93%, when the normal feed quantity of maize mixture was 5kg/s, the inlet wind speed of cleaning device was 12m/s, which met the national standard and the technical specification for quality evaluation of maize harvester. Cleaning rate of maize of polyurethane rubber sieve, which was increased by 16.33 percentage points through the comparison with metal sieve, was up to 95.3%.
