Authors

Abstract

To address the issue that existing seed-guiding devices struggle to meet the high-speed operational requirements of delta-row planters for dense maize planting, a seed-guiding device with air assistance and a guided groove was designed based on the principle of the brachistochrone. The overall structure and working principle of the device are described, and the curved segment of the seed guide tube was optimized using the brachistochrone principle while accounting for frictional effects. Computational fluid dynamics (CFD) simulations were conducted to analyse the flow field characteristics of the seed guide tube at inlet airflow velocities of 63.48, 60.64, 57.73, 54.69, 51.50, and 48.15 m/s. A multi-factor test was performed using chamber pressure and operating speed as test factors, with the qualified index of grain spacing and the coefficient of variation as evaluation metrics. Comparative tests were conducted using a traditional guided-groove seed guide tube and a brachistochrone-based seed guide tube without a guided groove. Results showed that the optimal parameter combination for the newly designed device was a chamber pressure of 3.124 kPa and an operating speed of 12.0 km/h. Under these conditions in the bench test, the qualified index reached 97.04%, and the coefficient of variation was 6.18%, outperforming the other two types of seed-guiding devices. These findings demonstrate that the seed-guiding device based on the brachistochrone principle can significantly improve the seeding quality of delta-row planters for dense maize planting under high-speed operation.

Abstract in Chinese

针对现有导种装置难以满足玉米品字形密植播种机高速作业需求的问题，基于最速降线原理设计了一种气辅-导槽式导种装置。阐述了导种装置的总体结构与工作原理，根据考虑摩擦力下的最速降线原理对导种管曲线段进行了优化设计，得到了曲线段轮廓的解析方程。通过CFD仿真试验探究了导种管在入口流速分别为63.48、60.64、57.73、54.69、51.50、48.15m/s时的流场特性。以腔室压力与作业速度为试验因素，以粒距合格指数、粒距变异系数为试验指标开展了多因素试验，确定了导种装置最优参数组合并对其进行了试验验证，同时开展了与传统导槽式导种装置、无导槽最速降线式导种装置的对比试验。结果表明：该导种装置的最优工作参数组合为腔室压力3.124 kPa、作业速度12.0 km/h，台架验证该参数组合下的粒距合格指数为97.04%、粒距变异系数为6.18%，并且较另外两种导种装置表现出了更优的导种性能，说明基于最速降线原理设计的气辅-导槽式导种装置可以进一步提高玉米密植播种机在高速作业条件下的播种质量。