Abstract:Aiming to address issues such as poor seed delivery stability and low seeding accuracy caused by seed collision with the inner wall of seed delivery tubes during high-speed operation of precision wheat strip seeders, a split air-assisted seed guiding system was designed. Key components of the guiding system were developed, and single-factor experiments were conducted by using a DEM-CFD coupled simulation method to determine the selection range of major structural parameters. Based on the results of single-factor tests, a Box-Behnken three-factor, three-level orthogonal combination simulation experiment was carried out to further determine the optimal structural parameter combination of the air- assisted seed guiding device. The experimental results showed that when the Venturi inlet pipe contraction section diameter was 16 mm, the contraction section length was 30 mm, and the Venturi inlet pipe jet angle was 25°, the seed delivery performance of the air-assisted guiding device was optimal, with a coefficient of variation for instantaneous flow consistency of 3. 82% and a coefficient of variation for seed mass flow stability of 4. 54% . The model was 3D printed, and bench tests were carried out to verify the optimal working range of the air-assisted seed guiding device. Bench test results indicated that with airflow assistance, the seed guiding uniformity of the device was significantly better than that without airflow assistance, with the optimal coefficients of variation for instantaneous flow consistency and seed mass flow stability reduced from 5. 82% and 5. 51% to 3. 51% and 3. 27% , respectively. Field test results showed that at an operating speed of 8 ~ 10 km/ h, the coefficients of variation for instantaneous flow consistency and the rate of seedling gaps did not exceed 4. 82% and 1. 95% , meeting the seed delivery performance requirements of the air-assisted guiding system. The research findings on this split air-assisted seed guiding device can provide guidance for subsequent design and performance improvement of split air-assisted seed guiding systems.
