摘要
为了提高气吸滚筒式排种器充种性能,以云南文山三七种子为研究对象,采用DEM-CFD耦合方法,以种子平均法向力方差和供种高度为指标,对气吹风压、振动频率、振动角度分别进行数值模拟,并对上述因素进行单因素试验,试验现象及效果与仿真分析结果一致。结果表明:气吹风压可以打破种群原有的稳定状态,从而降低种子瞬态的法向力即减小内摩擦力;振动频率增加种子平均法向力方差,即对种子的扰动性增强;合适的振动角度可以有效提高供种高度。减小内摩擦、增强种群扰动性、提高供种高度均可有效提高排种器充种性能。为寻找最佳参数组合,采用三因素五水平正交试验方法,对排种器排种性能进行试验,并对试验结果进行优化与验证。结果表明:在振动频率85 Hz、气吹风压3 k Pa、振动角度45°时,效果最佳,试验指标合格指数、漏播指数、重播指数可达93.02、1.42、5.56。
Panax notoginseng is one of rare medicinal herbs in China,and it is mainly grown in Yunnan Province. Market demand of Panax notoginseng is very large,and hence,until December 2014,the planting area of Panax notoginseng has reached 40 000 hm2. However,there is no precision seeding device suitable for Panax notoginseng. Seed-filling performance is the key factor that influences the properties of metering device. In order to improve the seed-filling performance of pneumatic cylinder seed-metering device,Yunnan Wenshan notoginseng seeds were adopted as sowing objects,the method of coupling DEM-CFD was used as research technique,meanwhile,variance yields of average normal stress and height of supplying seeds were considered as the optimizing targets. Through single factor experiment,the blowing wind pressure, vibration frequency and vibration angle were numerically simulated. It can be found that the experimental phenomenon and effect were in consistent with the simulation ones. Results showed that the blowing wind pressure can break the original steady state,thus reduce seeds transient normal stress which lower seeds internal friction; vibration frequency increases variance yields of average normal stress of seeds,hence disturbance of seeds was enhanced; and adequate vertical oscillation can effectively improve height of supplying seeds. Reducing internal friction,enhancing disturbance,improving height of supplying seeds can effectively improve the seed- filling performance. To find the best parameter combination,this paper used three factors and five levels orthogonal experimental method to test the metering performance,afterwards,the results of the test wereoptimized and verified. Results showed that at the vibration frequency of 85 Hz,blowing wind pressure of3 k Pa,vertical oscillation of 45°,experimental index is the best. Test indicators,including eligible index,missing index,multiple index can reach up to 93. 02,1. 42 and 5. 56,respectively.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第5期27-37,共11页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51305187)
云南省重点新产品开发计划项目(2014BC007)
云南省科技计划青年项目(2015FD011)
昆明理工大学自然科学研究基金项目(KKSY201323067
KKSY201323025
14118940)
关键词
三七
气吸滚筒式排种器
充种性能
数值模拟
Panax notoginseng
pneumatic cylinder seed-metering device
seed-filling performance
numerical simulation
