气吸式小麦精量排种器多侧清种机构设计与试验

Design and Experiment of Multi-side Seed-clearing Mechanism for Air-suction Precision Multi-grain Wheat Seed Metering Device

摘要:

针对目前小麦精量种植模式下机械式精量播种机在较高速（7 km/h）作业时，清种装置过清和漏清造成排种性能低的问题，本文优化设计了一种气吸式小麦精量排种器多侧清种机构，由内外侧、中部双侧鱼鳍状清种齿顶组成，通过多侧清种齿与籽粒团簇之间的机械碰撞，打破籽粒受力平衡，根除漏清现象，基于排种过程籽粒动力学分析和DEM-CFD耦合仿真，确定多侧清种机构关键结构参数，得出排种盘转速、中部双侧鱼鳍状清种齿顶距排种盘表面高度、清种齿齿顶锥角为影响清种性能的主要因素。采用最优性准则D-optimal设计方法进行仿真试验，得到最优参数组合：排种盘转速69.837 r/min、中部双侧鱼鳍状清种齿顶距排种盘表面高度6.125 mm、齿顶锥角4.48°时，合格率、漏播率、重播率分别为96.94%、2.34%、0.72%。选用"新冬52号"小麦籽粒进行台架验证试验，合格率、漏播率、重播率为94.8%、1.8%、3.4%;排种器田间试验结果表明，前进速度为7 km/h时，平均合格率91.19%，漏播率2.86%，排量一致性和稳定性符合行业指标，满足小麦精量种植要求。

Abstract:

Aiming to address the problem of reduced seeding performance in mechanical precision wheat seeders at relatively high operating speeds (7 km/h) due to over-clearing and missing-clearing by the seed-clearing device, a multi-side seed-clearing mechanism for an air-suction wheat precision seed metering device was optimized and designed.The mechanism consisted of inner-side, outer-side, and middle double-side fish-fin shaped seed-clearing teeth.Through mechanical collisions between the multi-side clearing teeth and seed clusters, the force balance of the grains was disrupted, effectively eliminating missing-clearing phenomena.Based on dynamic analysis of seed motion during the seeding process and DEM-CFD coupled simulation, the key structural parameters of the multi-side seed-clearing mechanism were identified.The main factors influencing seed-clearing performance were determined to be the seeding disc rotational speed, the installation height of the middle double-side fish-fin shaped seed-clearing teeth from the seeding disc surface, and the apex taper angle of the seed-clearing teeth.Simulation experiments were conducted using the D-optimal optimality criterion, yielding the optimal parameter combination: seeding disc rotational speed of 69.837 r/min, apex height of the middle double-side fish-fin shaped seed-clearing teeth of 6.125 mm from the seeding disc surface, and apex taper angle of 4.48°.Under these conditions, the qualified rate, missing seeding rate, and reseeding rate were 96.94%, 2.34%, and 0.72%, respectively.Bench validation tests were performed using "Xindong 52" wheat seeds, resulting in a qualified rate of 94.8%, missing seeding rate of 1.8%, and reseeding rate of 3.4%.Field performance tests of the seed metering device at a forward speed of 7 km/h showed an average qualified rate of 91.19%, a missing seeding rate of 2.86%, with seeding quantity consistency and stability conforming to industry standards, thereby satisfying the requirements for precision wheat planting.