小麦分体式气流辅助导种装置设计与试验

Design and Experiment of Wheat Split Air-assisted Seed Guiding Device

摘要:

针对小麦精量条播机高速作业导种过程种子流管壁碰撞,导致输种稳定性差、排种精度低等问题,设计了一种分体式气流辅助导种系统。对导种系统关键部件进行设计,并通过DEMCFD耦合仿真法开展单因素试验,确定主要结构参数选取区间。基于单因素试验结果开展了Box-Behnken三因素三水平正交组合仿真试验,进一步确定气流辅助导种装置最优结构参数组合。试验结果表明:文丘里进气管收缩段直径为16mm、收缩段长度为30mm、进气管吹射角度为25°时,瞬时排量一致性变异系数为3.82%,种子质量流稳定性变异系数为4.54%,气流辅助导种装置输种性能最佳。对模型进行3D打印,并开展台架试验验证气流辅助导种装置最优工作区间,台架试验结果表明,在有输送气流辅助导种情况下导种装置导种均匀性明显优于无气流辅助导种的导种装置,最优瞬时排量一致性变异系数和种子质量流稳定性变异系数分别由5.82%、5.51%降至3.51%、3.27%,田间试验结果表明,作业速度在8~10km/h时,瞬时排量一致性变异系数和出苗断条率均不高于4.82%、1.95%,符合气流辅助导种系统输种性能要求。

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.