Analysis of the seed filling performance influenced by maize seed shape, posture, and suction force

This study addresses the issue that during the seed filling process of air-suction seed metering devices, maize seeds are randomly adsorbed by suction holes, leading to various filling postures. This randomness contributes to a significant amount of multiple seeding and leakage. The relationship between the maize seed filling posture and the overall filling performance has remained unclear until now. This research establishes, for the first time, the laws governing the impact of maize seed posture and suction force on seed filling performance. A Computational Fluid Dynamics (CFD) model is developed to simulate maize seeds in different postures within a single-phase airflow field. Subsequently, a validation experiment, using a custom-built suction force measurement device, was conducted to analyse the effects of negative pressure, suction distance, and seed posture on the suction force. The findings indicated that discrepancies between the simulated and experimental results of suction force are within 5 × 10⁻³ N, thereby confirming the accuracy and reliability of the CFD model. Moreover, the relative error of the suction force fitting equations derived from the experimental data was found to be < 10 %. The experiment on seed filling performance also determined that a higher proportion of maize seeds lying flat in their filling posture correlated positively with the seed filling pass rate of the metering device.