摘要
为研究种子在油麦兼用气送式集排器输种管道中的迁移规律,运用EDEM-CFD耦合仿真方法分析了输种管道直径、长度、横纵管道长度比(k)和接头形式对种子运动特性和气流场的影响;台架试验研究了输种管道结构对排种性能的影响。结果表明:种子在输种管道中受力与速度主要沿管道轴线方向,与气流速度相同,种子迁移的动力主要源自流体阻力。管道出口处种子速度随k增加呈先降后升的趋势,输种管道结构显著影响各行平均排种量和各行排量一致性变异系数。当输种管道直径、长度和k分别为42 mm、1.0 m和2/3时,管道出口处种子速度、两相流相对速度和压强损失较小,排种性能较优。接头为弯管的输种管道出口处种子速度明显高于接头为折线形管道,两相流相对速度表现为弯管低于折线形接头;弯管半径100 mm的输种管道气流场和种子分布均匀,压强损失较小。供种装置转速为10~40 r/min时,排种油菜、小麦时各行排量一致性变异系数分别低于4.0%和5.0%,总排量稳定性变异系数和种子破损率分别低于1.0%和0.1%。
In order to study seed movement law of seed conveying tube of air-assisted centralized metering device for rapeseed and wheat, effects of seed conveying tube＇s diameter and length, ration of lateral length to longitudinal length （k） , and joint＇s type on seed motion characteristics and airflow field were analyzed with EDEM - CFD coupling approach. Impact of seed conveying tube＇s structure on seeding performance was studied by bench experiments. The results showed that seed movement direction which was the same as airflow direction in seed conveying tube was in axis direction and seed motion source was the drag force. The seed velocity in seed conveying tube＇s outlet was increased first and then decreased with the increase of ratio of lateral length to longitudinal length （k）. The each row＇s averaged seeding quantity and apiece row consistency variation coefficient of seeding quantity were affected significantly by seed conveying tube＇s structure. When seed conveying tube＇s diameter, length and k was 42 ram, 1.0 m and 2/3, respectively, seed velocity, relative velocity between particle and airflow and seed distribution were good with lower pressure loss and better seeding performance. Seed velocity of conveying tube with bends was larger than that of conveying tube with mansard joint. The relative velocity of conveying tube with bends was lower than that of conveying tube with mansard joint. Airflow field and seed distribution was uniform with larger seed velocity and lower pressure loss in conveying tube with bends of 100 mm of radius. When rotational speed of seed feed device was within the range of 10 - 40 r/min, apiece row consistency variation coefficient of seeding quantity of rapeseed and wheat was less than 4.0% and 5.0% , respectively. The stability of full seeding quantity and seed damage rate were no more than 1.0% and O. 1%, respectively, for both rapeseed and wheat. The results provided the basis for structure optimization of air-assisted centralized metering system and improveme
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第3期57-68,共12页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51575218
51275197)
国家油菜产业体系专项(CARS-13)
湖北省技术创新专项(2016ABA094)
'十二五'国家科技支撑计划项目(2013BAD08B02)
关键词
油菜
小麦
气送式集排器
输种管道
气固两相流
排种性能
rapeseed
wheat
air-assisted centralized metering device
seed conveying tube
gas - solidflow
seeding performance
