基于DEM-MBD耦合的链勺式人参精密排种器研究

Design and Test of Chain-spoon Type Precision Seed-metering Device for Ginseng Based on DEMMBD Coupling

人参播种中存在因人参种子形状不规则、流动性差,种子在播种前需进行催芽处理,催芽的种子易损伤,造成充种困难、易伤种等问题,为此设计一种链勺式人参精密排种器。通过对充种过程中种子受力情况和运动状态的分析,阐明倾斜充种可提高充种性能的机理;通过对携种过程的理论计算和力学分析,并基于DEM-MBD耦合的单因素仿真试验,分析了不同排种链条的张紧力、不同排种器结构参数和工作参数对其工作性能的影响,确定了链勺式排种器的结构参数;以主动链轮转速、充种倾角和种层高度为试验因素,以充种的单粒率(1粒/勺)、复充率(≥2粒/勺)、漏充率(0粒/勺)为试验指标,基于DEM-MBD耦合进行了二次回归正交旋转组合仿真试验。结果表明:影响单粒率的主次顺序为充种倾角、主动链轮转速、种层高度;当充种倾角为71.73°、主动链轮转速为79.10 r/min、种层高度为84.28 mm时,充种性能最佳,单粒率为95.68%、复充率为3.57%、漏充率为0.75%;为验证排种器的工作性能,进行了台架试验,结果表明链勺式人参精密排种器的工作性能较好,满足我国非林地人参种植的播种要求。

Because of irregular shape and poor fluidity of ginseng seeds,the seeds need to be spewed before sowing.The spewed seeds are easy to be damaged,resulting in difficult seed filling and easy seed damage.A chain-spoon type precision seed-metering device for ginseng was designed.Through the analysis of the force and motion of seeds in the process of seed filling,the mechanism of tilting filling-seed improving the filling-seed performance was expounded.And through theoretical calculation,static and dynamic analysis of seed carried by seed’s spoon was done,and the single factor simulation test was conducted through the DEM-MBD coupling.The influence of different structural parameters and working parameters of seed-metering device on its working performance were analyzed and the structural parameters of chain-spoon type precision seed-metering device were ascertained.Based on DEM-MBD coupling simulation,the quadratic regression orthogonal rotation combination test was done,with the rotation rate of drive sprocket,filling-seed angle and seed's height as the test indexes.Experimental results showed that the primary and secondary order of influencing conformity index was filling-seed angle,rotation rate of drive sprocket and seed's height.When filling-seed angle was 71.73°,the rotation rate of drive sprocket was 79.10 r/min and seed's height was 84.28 mm,filling-seed performance was the optimum,and the single grain rate was 95.68%,the refilling rate was 3.57%,and the missing filling rate was 0.75%.The bench test was conducted to testify the working performance of seed-metering device,which showed that the chain-spoon type precision seed-metering device for ginseng had better performance on filling-seed and can meet the requirements of non-forest ginseng sowing.