组合孔内充式油莎豆排种器设计与试验

Design and Experiment of Seed Metering Device with Combination Hole and Inner Filling for Cyperus esculentus

针对油莎豆种子表面凹凸不平、形状不规则导致的流动性差,种群压实导致充种性能不佳和每穴3粒种子投种时轴向分散等问题,设计了一种组合孔内充式油莎豆排种器。对复式型孔的外孔和内孔长度进行了设计,提高了充填性能;基于最速降线原理设计了回流板曲面,理论分析了回流板上端倾角范围、安装位置及种子在回流板上运动情况;分析了种子与强制排种装置碰撞过程,设计优化了强制排种装置。利用EDEM仿真分析了种群回流运动过程和强制排种过程,探明了回流板种群运动过程,得出在倾斜角为32°的回流板安放位置回流效果较好,表明回流板可以增强种群流动性,避免种群堆积;分析证明了强制排种装置可提高排种器的集穴效果,实现3粒投种一致性。最后进行了投种一致性高速摄影试验、排种轮单排孔排种试验、双因素试验和集穴试验,通过高速摄影分析了油莎豆种子位移及速度变化规律,其结果与数值模拟基本一致,从排种轮单排孔排种试验得出3排型孔排种合格率差异不显著,双因素试验得出在复式型孔内孔长度为8 mm、转速为20 r/min条件下,排种器合格指数、漏播指数、重播指数可达96.4%、1.5%和2.1%。在较优内窝孔长度和回流板条件下进行集穴试验,试验结果表明在转速为10、20 r/min时集穴效果最佳。

Aiming at the problems of poor mobility caused by uneven surface and irregular shape of seeds,poor seed filling performance caused by population compaction and axial dispersion of three seeds per hole,a combined hole filled seed metering device was designed.The length of the outer hole of the inner socket was designed to improve the filling performance.Based on the principle of the brachistochrone,the surface of the backflow plate was designed,and the range of the upper end inclination of the backflow plate,the placement position and the movement of the seed on the backflow plate were theoretically analyzed.The collision process between seed and forced seed metering mechanism was analyzed,and the gathering seed metering mechanism was designed and optimized.The population backflow movement process and gathering seeding process were analyzed by EDEM simulation,and the population movement mechanism with backflow plate was proved.It was concluded that the backflow effect of backflow plate with an inclination of 32°was better,indicating that the backflow plate could enhance population mobility and avoid population accumulation.The analysis proved that the gathering seed metering mechanism can improve the hole collection effect of the seed metering device and achieve the consistency of three seeds.At last,the high-speed photography experiment of seed throwing consistency,single hole test,double factor experiment and acupoint gathering test were carried out.Through high-speed photography,the law of displacement and speed change of Cyperus esculentus seeds was analyzed.The results were basically consistent with the numerical simulation.From the single hole seed metering wheel seed metering experiment,it was found that there was no significant difference in the seed metering qualification rate of three rows of holes.The double factor experiment showed that when the inner hole length of the double hole was 8 mm and the rotational speed was 20 r/min,the qualified index,missing index and multiples index of the seed metering device can reach 96.4%,1.5%and 2.1%,respectively.Under the conditions of better inner cavity length and reflux plate,the experiment results showed that the best effect was at speed of 10 r/min and 20 r/min.