Authors

Abstract

To enhance the seeding accuracy of multi-seed-per-hole operations for small-seed crops, a combined experimental-CFD optimization method for an air-suction seed metering plate was developed. Single-factor tests established that the suitable suction-hole diameter was 0.4-0.6 times the equivalent seed diameter, and threshold-based negative-pressure tests were used to define the acceptable suction-hole negative-pressure range for millet, broomcorn millet, and rapeseed. CFD pressure-tracing analysis was then performed to quantify the mapping between suction-hole pressure and air-chamber inlet negative pressure. On this basis, a three-factor, three-level optimization test was conducted using inlet negative pressure, suction-hole diameter, and suction-hole thickness as variables, with the qualification rate of suction-hole pressure as the response. The optimized parameter combinations were 2.51 kPa, 0.88 mm, and 0.31 mm for millet; 2.97 kPa, 1.12 mm, and 0.35 mm for broomcorn millet; and 2.35 kPa, 0.93 mm, and 0.32 mm for rapeseed. Bench validation showed seed-filling rates of 93%, 97%, and 96%, respectively. The results demonstrate that the proposed method can effectively reduce empirical trial workload and provide a practical basis for the design of pneumatic precision seed metering plates for small-seed crops.

Abstract in Chinese

为提高小籽粒种子一穴多粒播种作业的准确性，本文通过排种盘吸孔的单因素试验，确定了适宜的负压范围和吸孔直径范围，并基于影响作业性能的主要因素开展了正交仿真试验与优化分析。结果表明，吸孔直径与种子粒径之间存在一定匹配关系，即dk=(0.4–0.6)dz。针对排种盘吸孔对三类种子的负压吸附特性，建立了负压吸附性能评价标准，并通过构建排种盘负压吸附试验平台，获得了各类种子的适宜负压范围。为进一步揭示吸孔负压与排种器气室吸气口负压之间的关系，基于Fluent软件对排种器气室流场进行了数值模拟与流场分析，确定了不同种子对应的气室吸气口负压范围。在此基础上，以吸气口负压、吸孔直径和吸孔厚度为试验因素，以吸孔处负压合格率为评价指标，开展了三因素三水平正交试验，获得了三种小籽粒种子的最优参数组合。最后通过验证试验，得到了三种种子充种合格率分别为93%、97%和96%，验证了研究的准确性。