DEM-CFD simulation and seed orientation evaluation of a self-suction wheat shooting device

Planting performance is essential for wheat sowing and seedling germination. The seed motion and sowing posture also influenced the sowing performance. In this study, a DEM-CFD coupling simulation model was conducted to investigate the seed motion characteristics in a self-suction wheat shooting device. The seed orientation and shooting angle were selected to evaluate the seed motion characteristics. The seed orientation decreased with increasing rotational speeds and gradually decreased during the seed filling and cleaning. The orientation angle increases slightly in the seed acceleration process. Specifically, the orientation angles are 19.8°, 19.1° and 18.6°, respectively, under the rotational speeds of 800, 1000 and 1200 rpm at the end of the acceleration process. The shooting angle increases with the increase of the shooting device's forward speed and rotational speed. The increase in forward speed and rotational speed increases the seed velocity. Most seed particles with shooting angles from 60° to 90°, accounted for >90% of the seed number, which depicts that the seed-filling performance is promoted with the increasing rotational speed of the blade. A validation experiment was conducted to investigate the shooting performance of the self-suction shooting device Afterward. The shooting performance, including the coefficient of variation of the shooting depth (CVSD), coefficient of variation of the seed shooting amount (CVSA) and shooting depth (SD) were analyzed. The results showed that the shooting performance of the self-suction device could fully meet the shooting requirements of winter wheat in the North China plain. Specifically, the CVSD, CVSA and SD were 5.2%, 5.3% and 31.2 mm, respectively, under the rotational speed of 1200 rpm. The approach is providing a new sustainable and noncontact method for sowing wheat.