基于EDEM-CFD耦合的内充气吹式排种器优化与试验  

Optimization and Experiment of Inside-filling Air-blowing Seed Metering Device Based on EDEM-CFD

作　　者：韩丹丹[1] 张东兴[1] 杨丽[1] 崔涛[1] 丁友强 卞晓慧 

机构地区：[1]中国农业大学工学院,北京100083

出　　处：《农业机械学报》2017年第11期43-51,共9页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51375483;51575515);现代农业产业技术体系建设项目(21226003);农业部土壤-机器-植物系统技术重点实验室项目

摘　　要：针对内充气吹式排种器对圆形种子适应性差、排种效果不佳的问题,对内充气吹式排种器进行优化设计,为增强种子充填容积和气流压附力在型孔底部开设不同结构的槽孔。基于离散单元法理论建立玉米籽粒粘结颗粒模型,运用EDEM-CFD耦合分析方法,以型孔内种子在排种盘转动过程中所受的曳力值为指标,在入口风速为30 m/s、前进速度为8 km/h的工作条件下对3种不同型孔结构排种盘进行圆粒种子排种效果的耦合仿真,分析排种过程中圆粒种子所受曳力的变化情况及清种和压种性能。仿真结果表明:同一排种盘中,因大圆粒种子迎风面积大于小圆粒种子,所受曳力均大于小圆粒,迎风面积大的颗粒更易被清出型孔;径向内开方孔盘型孔内气流对颗粒的曳力及压附力均较大,且增大了型孔对种子在径向方向的充填容积,该盘对圆粒种子及混合种子的工作效果均较好。为验证仿真结果进行台架试验,当前进速度为8 km/h时进行3种排种盘工作压强的单因素试验,结果表明,径向内开方孔盘合格率随工作压强的增大而增大,当工作压强大于5.5 k Pa时,合格率超过95%,明显优于其他2个排种盘;对径向内开方孔盘进行前进速度为4~12 km/h、工作压强为4~8 k Pa的双因素试验,结果表明,合格率随着前进速度和工作压强的增大而增大,针对不同前进速度,当工作压强高于6 k Pa时,合格率接近96%,漏播率低于1%。According to the present situation of the sowing effect of original inside-filling air-blowing seed metering device for flat seeds is better than circles,the phenomenon of drag force greatly affects the cleaning and pressing effect was found through the force analysis of seed in cleaning and pressing process for optimization the sowing effect of circle and mixed seeds. For analyzing the changing of drag force of different seed metering discs in the process of working under the same operational parameter,the bonded particle model was used to model maize based on theory of discrete element method,the coupling analysis method of EDEM-CFD was applied to couple simulation circle seeds with three different hole structures of seed metering discs. The value of drag force of seed in the hole during rotation of seed metering disc was taken as indicator,the changing situation of drag force of seed was analyzed under the operational parameter of inlet air velocity was 30 m/s and forward speed was 8 km/h with different seed metering discs. Simulation results showed that the drag force of big circle seed was larger than that of small circle due to different particle windward areas in the same type seed metering disc under the same working conditions. In other words,large granular seeds were more likely to be cleaned out of holes. Based on cleaning and pressing performance analysis of different seed discs,the drag force and pressing force in the hole of seed disc with block slot were both larger. And due to the volume of seed filling in the holes wasincreased compared with other discs,the effect of seed disc with block slot sowing circle and mixed seeds were both better through simulation. The single factor test of working pressure was carried out when forward speed of the different seed discs was 8 km/h,experimental results showed that the qualified rate of seed disc with block slot was increased gradually with the increase of working pressure,which was better than the other two. The full factorial experiments were conducted o

关 键 词：精量排种器 内充气吹式 离散单元法 EDEM-CFD 结构优化 

分 类 号：S223.2[农业科学—农业机械化工程]