Design of conical seed separator plate for wide belt seeder based on DEM and experiment

Wide belt sowing is an innovative method to improve production. In order to ensure uniform for wheat wide belt sowing, this paper proposed a conical seed separator plate and optimized its critical structural parameters. Firstly, a mathematical model of conical seed separator plate was established, with cone radius, cone angle and installation angle as variables. Secondly, a simulation model based discrete element method (DEM) was developed to evaluate wheat sowing uniformity using lateral variation coefficient (LVC), and single factor simulation experiment with three variables were conducted to determine the optimal range of structural parameters. Finally, optimal structural parameters were confirmed through orthogonal simulation experiment, and validated through indoor and field experiments. In field experiments, the emergence rate was monitored at different sowing depths after the wheat was sown. The results of single factor experiment showed that the optimal LVC was obtained when cone radius ranged from 70 to 80 mm, cone angle ranged from 40° to 60° and installation angle ranged from 30° to 40°. The results of orthogonal simulation experiment showed that the primary and secondary order of the influence of each factor on LVC was installation angle, cone angle and cone radius. The corresponding parameter values after optimization were 74.82 mm for cone radius, 49.61° for cone angle and 34.18° for installation angle, with a regression predicted LVC of 12.36%. To validate the optimized parameters, simulation validation, indoor experiment and field experiments by self-made field in situ multifunctional test bench with no-till wide belt sowing and rotary tillage wide belt sowing were conducted, obtaining LVC of 12.28%, 14.73%, 16.28% and 16.89%, respectively. For emergence rate, the sowing depth of 4 cm was highest. Rotary tillage promoted emergence than no-till. These findings can provide guidance for optimizing the structural parameters of seed separator plate in wide belt seeders.