Grid division dimensions.

The use of pneumatic seeders for coated grass seed effectively addresses the challenge of seed establishment in arid and semi-arid regions, significantly contributing to the mitigation of soil desertification. However, during pneumatic seeder operations, high airflow velocities can lead to increased seed breakage rates, while low airflow velocities may result in blockages. To address these issues, this study employs both experimental and simulation methods to optimize the pneumatic conveying system of the seeder. A theoretical model of the pneumatic conveying system was developed to analyze the velocity field, pressure field, and seed trajectory within the flow field. The study focused on optimizing three parameters: Diameter of the throat outlet, diameter of the throat inlet, and the seed inlet angle. The key findings are as follows: (1) An optimized throat diameter of D2 = 58 mm is less prone to blockage; (2) Optimization of the neck ratio does not effectively mitigate the blockage issue; and (3) A seed inlet angle of α = 77° reduces seed breakage. This research elucidates the mechanisms of airflow and seed distribution within the pneumatic conveying system, providing solutions to minimize seed breakage and blockage, thereby enhancing the design and broader application of pneumatic seeders.采用气力播种机（pneumatic seeder）播撒包衣草种，可有效解决干旱半干旱地区的牧草建植难题，对减缓土壤荒漠化进程具有重要推动作用。然而在气力播种机作业过程中，气流速度过高会提升种子破损率，过低则易引发输送管路堵塞。为解决上述问题，本研究结合实验与仿真两种手段，对播种机的气力输送系统开展优化研究。本研究建立了气力输送系统的理论模型，用于分析流场内的速度场、压力场与种子运动轨迹。本次优化聚焦于三个核心参数：喉管出口直径、喉管入口直径以及种子入口角度。主要研究结论如下：(1) 优化后的喉管直径D2=58mm不易发生堵塞；(2) 喉颈比优化未能有效缓解管路堵塞问题；(3) 种子入口角度α=77°可降低种子破损率。本研究阐明了气力输送系统内气流与种子的分布机理，为降低种子破损率与堵塞问题提供了可行方案，有助于提升气力播种机的设计水平与推广应用范围。