大豆玉米带状复合种植模式下仿生减阻破茬防堵装置设计与试验

Design and Experiment of Bionic Drag-reducing, Stubble-breaking and Anti-blocking Device under Soybean-Maize Strip Intercropping System

摘要:

针对西南地区耕地地块零散、土壤黏重、秸秆覆盖量大且以整秆覆盖为主等特点,结合大豆玉米带状复合种植免耕播种作业需求,设计了一种费马螺线型仿生减阻破茬防堵装置。基于滑切切割理论构建费马螺线型破茬刀刃口曲线,并以疑布甲虫翅鞘表面非光滑结构为仿生对象,设计楔形仿生减阻单元。建立“秸秆与根茬-黏重土壤-破茬装置”离散元耦合模型,采用二次回归正交旋转组合试验,对机组前进速度、破茬刀转速及刃口角度等关键参数进行优化分析。正交试验结果表明,当机组前进速度为0.91m/s、破茬刀转速为225r/min、刃口角度为25.2°时, 破茬刀对根茬的粘结键断裂数量为21470,作业功率为5.82 kW。田间试验结果表明,在平均秸秆覆盖率为94%、整秆覆盖量为0.575kg/m2条件下,装置对玉米-大豆秸秆的平均切断率为92.98% ,较传统缺口型圆盘破茬刀提高50.91%,作业过程中通过性良好,满足西南地区免耕播种作业要求。研究揭示了费马螺线刃口滑切特性与仿生减阻单元协同作用机制,验证了仿生曲线刀具在高覆盖、黏重土壤条件下的减阻防堵优势,为西南丘陵地区免耕播种机关键部件的结构创新与参数优化提供了理论依据与技术支撑。

Abstract:

Aiming to address the characteristics of fragmented farmland plots, heavy clay soil, and extensive straw coverage ( primarily whole-stalk coverage) in the southwestern region, a bionic drag- reduction anti-clogging device based on the Fermat spiral was designed to meet the requirements of no-till seeding for soybean-corn strip intercropping. The cutting-edge curve of the stubble-breaking blade was constructed based on sliding-cutting theory, and a wedge-shaped biomimetic drag-reducing unit was designed, inspired by the non-smooth surface structure of the Tenebrionidae elytra. A discrete element coupling model of “multi-crop residues-heavy clay soil-residue-clearing device” was established, and a second-order orthogonal rotation combination experiment was conducted to optimize key parameters, including the forward speed of the machine, the rotational speed of the stubble-breaking blade and the blade edge angle. The orthogonal experimental results showed that when the forward speed was 0.91m/s, the rotational speed of the stubble-breaking blade was 225r/min, and the blade edge angle was 25.2°, the number of bonding breaks between the stubble-breaking blade and root residues reached 21470, with an operational power of 5.82kW. Field tests demonstrated that under conditions of an average straw coverage rate of 94% and a whole-stalk coverage of 0.575 kg/m2, the device achieved an average cutting rate of 92.98% for corn-soybean straw, representing a 50.91% improvement compared with that of traditional notched disk blades. The device exhibited good passability during operation, meeting the requirements of no-till seeding in the southwestern region. The results revealed the synergistic mechanism between the sliding-cutting characteristics of the Fermat spiral cutting edge of the stubble- breaking blade and the biomimetic drag-reducing structure, validating the advantages of biomimetic curved stubble-breaking blade in reducing drag and preventing blockage under conditions of high straw coverage and heavy clay soil. The research result can provide theoretical support and technical foundation for the structural innovation and parameter optimization of key components of no-till seeder in hilly regions of southwestern China.