| 基于EDEM软件的气压组合孔式排种器充种性能模拟与验证 |
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| 引用本文： | 史 嵩,张东兴,杨 丽,崔 涛,李克鸿,殷小伟.基于EDEM软件的气压组合孔式排种器充种性能模拟与验证[J].农业工程学报,2015,31(3):62-69. |
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| 作者姓名： | 史 嵩 张东兴 杨 丽 崔 涛 李克鸿 殷小伟 |
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| 作者单位： | 中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083,中国农业大学工学院,北京 100083 |
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| 基金项目： | 国家自然科学基金资助项目（51375483）;科技部"十二五"农村领域国家科技计划项目（2013BAD08B01-3）;农业部土壤-机器-植物系统技术重点实验室资助项目 |
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| 摘 要： | 为研究种群扰动对排种器充种性能的影响,该文基于离散单元法理论,以气压组合孔式排种器为模型,运用EDEM软件对4种不同型孔结构排种盘的种群运动进行了仿真分析,以种子法向应力跳动量和种子平均法向应力总和作为指标,分析了各排种盘在不同转速条件下的种群内摩擦力的变化,仿真结果表明,种群扰动强度的增大并不能显著减少种子法向应力的总量,但会降低种子瞬态的法向应力即瞬时种子内摩擦力,据此推断出扰动强度最大的排种盘的充种性能较其他排种盘更优。在排种器试验台上进行了验证试验,选取6种转速,以漏充率为指标,分别对4种排种盘进行试验,结果显示扰种强度最高的排种盘在各转速条件下的漏充率最低。对比仿真与试验结果发现,增强排种盘对种群的扰动可以在一定程度上提高种子的充种性能。
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| 关 键 词： | 农业机械 种子 试验 精量排种器 充种性能 数值模拟 |
| 收稿时间： | 2014/9/24 0:00:00 |
| 修稿时间： | 2014/12/26 0:00:00 |
Simulation and verification of seed-filling performance of pneumatic-combined holes maize precision seed-metering device based on EDEM |
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| Shi Song,Zhang Dongxing,Yang Li,Cui Tao,Li Kehong and Yin Xiaowei.Simulation and verification of seed-filling performance of pneumatic-combined holes maize precision seed-metering device based on EDEM[J].Transactions of the Chinese Society of Agricultural Engineering,2015,31(3):62-69. |
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| Authors: | Shi Song Zhang Dongxing Yang Li Cui Tao Li Kehong and Yin Xiaowei |
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| Institution: | College of Engineering, China Agricultural University, Beijing 100083, China,College of Engineering, China Agricultural University, Beijing 100083, China,College of Engineering, China Agricultural University, Beijing 100083, China,College of Engineering, China Agricultural University, Beijing 100083, China,College of Engineering, China Agricultural University, Beijing 100083, China and College of Engineering, China Agricultural University, Beijing 100083, China |
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| Abstract: | Abstract: Pneumatic metering device has been increasingly widespread for the advantages of high planting quality, low seed-injuring rate, strong adaptability to seeds and higher planting speeds when sowing corn seeds. The seed-filling performance of pneumatic metering device is particularly important which basically determines the seeding performance. Studies have shown that motion characteristics of seeds have a greater influence on the seed-filling performance, however, the shape of corn seeds is very irregular and the physical properties of material system of such discrete-state particle are too complicated to describe with conventional motion law of solid and liquid substance. This paper studied the pneumatic-combined holes seed-metering device based on the theory of discrete element method. The EDEM software was used to carry out simulation research, and the Hertz-Mindlin no-slip contact model was selected and the normal force between particles contacts was used as monitoring value of internal friction during the simulation. Four kinds of seed plates with great differences of type hole structures were designed which aimed at creating different interference intensity. The seeds of Zhengdan 958, which was widely adopted, were used as modeling objects of particles. The impact of seeds plates on seeds movement was simulated at different rotational speeds, and variance value of normal force and total normal force were used as indexes for data analysis during simulation. The results indicated that the increase of seeds' interference intensity can't significantly reduce the total normal force but will reduce the transient normal stress of seeds which is also called transient internal friction. It is inferred that the seed-filling performance of D type seeds plate which has the largest variance value of normal force is better than the others. The four kinds of seeds plates were respectively processed and installed on the pneumatic-combined holes seed-metering device to do experiments. The inspection area was designated before experiments, and predetermined the position where type hole leaving away from the seed layer as a starting point and the beginning of seed-clearing area as the end point, and then a High-Speed Video Camera was used to record images of this area and determined the situation as missing-seeding when there was no seeds in the type holes in this region. Experiment results indicated that variance value of normal force has a significantly impact on missing-seeding rate of seeds plate, and the value variance of D type seeds plate was the largest, the missing-seeding rate reached the lowest rate 1.13% when the rotational speed reached the maximum value 37.3 r/min. By comparing the simulation results and experimental results, the relationship among the missing-seeding rate, the rotational speed of seed plate and variance value of normal stress was obtained which verified the simulation conclusion that larger interference intensity can reduce the internal friction of seeds instantaneously and improve the seed-filling rate of metering device. |
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| Keywords: | agricultural machinery seed experiments precision seed-metering device seed-filling performance numerical simulation |
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