Influence of surface slope on the seeding performance of air-assisted centralized metering device for rapeseed based on numerical simulation

The change in surface slope during the broad width operation of the rapeseed planter significantly influences the seeding performance of the air-assisted centralized metering device. This study, focusing on the air-assisted centralized metering device, established stationary random process models for the feeding rate and uniforming rate. Using EDEM simulation, experiments were conducted on the combined influence of front-rear tilt angle and feeding device rotating speed, as well as lateral tilt angle and feeding device rotating speed, on the feeding rate. A mathematical model was established to reflect the influence of front-rear tilt angle and feeding device rotating speed on the feeding rate. The experimental results showed that, with a flat surface as the benchmark, the change in feeding rate reached 50% when the absolute value of the front-rear tilt angle was between 3° and 5°. When the lateral tilt angle was between −5° and 5°, the increase rate of the feeding rate was no more than 6.43% relative to the non-tilt state. A DEM-CFD coupled simulation was used to analyze the influence of tilt angle on the uniforming performance. The simulation experiment showed that the uniformity coefficient of variation (CV) of the seed quantity in each row gradually increased within the range of 4.99% to 14.57% with the increase in tilt angle. Using the comprehensive performance testing platform of the planter, the seeding performance of the planter under different field surface slopes was simulated. The results showed that the seeding performance during changes in surface slope was jointly affected by the feeding performance and uniforming performance. With the increase in the range of one-way oscillation angle and reciprocating oscillation angle, the uniformity CV of seeding mass in each row gradually increased within the range of 6.68% to 10.71% and 4.86% to 10.48%, respectively. The relationship models between the seeding mass of front-rear one-way oscillation, the seeding mass of front-rear reciprocating oscillation, and the front-rear tilt angle and feeding device rotating speed were determined, making the seeding mass on slope converge with that on flat surfaces.