【作者】 刘敏；

【导师】 侯占峰；

【作者基本信息】 内蒙古农业大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 种子丸粒化技术是以种子为核心,基于丸粒化包衣设备,将种衣药剂、粉料、以及其他添加剂均匀有效的包裹在种子表面的加工处理技术。种子丸粒化不仅可以提高种子发芽率,保护种子免受外界生物或非生物的胁迫,同时适用于精量播种,保证在机械输送过程中种子的完整性。本文对紫花苜蓿种子与包衣粉料进行离散元仿真参数标定,研究种、粉间混合机理和评价指标,实现相关设备的工作、工艺参数优化,以提高紫花苜蓿种子单籽丸化合格率和丸化包衣效果,主要完成工作如下:1.通过物理试验测得紫花苜蓿种子的物性参数,利用EDEM软件建立紫花苜蓿种子模型与休止角仿真模型,使用Hertz-Mindlin无滑移接触模型依次开展Plackett-Burman试验、最陡爬坡试验与Box-Behnken试验得到紫花苜蓿种子最佳接触参数组合。2.通过物理试验测得包衣粉料的物性参数,采用Hertz-Mindlin with JKR接触模型,依次开展Plackett-Burman试验、最陡爬坡试验与Box-Behnken试验得到包衣粉料最佳接触参数组合。标定紫花苜蓿种子与包衣粉料间的接触参数时将物理试验与仿真试验相结合,通过二次回归拟合方程得到其接触参数。3.从理论上分析种粉间混合机理,以变异系数为评价指标,开展单因素试验确定种子丸粒化包衣工作参数取值范围;进行Plackett-Burman试验,从包衣锅振动频率、包衣锅振动幅值、包衣锅振动方向、包衣锅转速、包衣锅倾角中筛选出对响应值存在显著性影响的工作参数为:包衣锅倾角、包衣锅转速与包衣锅振动频率。4.根据单因素试验和Plackett-Burman试验结果,分别以丸化合格率与变异系数为响应值,开展不同包衣工作参数二次回归正交试验,得到紫花苜蓿种子最佳丸化包衣工作参数组合为:包衣锅转速为58r/min,包衣锅倾角为34°,包衣锅振动频率为15Hz;以单次供粉量、单次供液量与包衣时长为试验参数,开展正交试验,得到紫花苜蓿种子最佳丸化包衣工艺参数为:单次供粉量最佳值为10g、单次供液量最佳值为10ml、包衣时长最佳值为5min。更多还原

【Abstract】 Seed pelletizing technology is a seed-based processing technology that wraps seed coating chemicals,powders,and other additives evenly and effectively on the seed surface,based on the pelletizing coating equipment.Seed pelletizing not only improves seed germination and protects the seed from external biotic or abiotic stresses but is also suitable for precision sowing and ensures the integrity of the seed during mechanical transport.In this thesis,calibrate the discrete element simulation parameters of alfalfa seeds,and coating powder,the mixing mechanism and evaluation index between seeds and powder are studied,and the work of related equipment and process parameters are optimized to improve the qualification rate of alfalfa seed single-seed pelletization and the pelletization coating effect,the main work accomplished is as follows.1.The physical parameters of alfalfa seeds are measured by physical tests,and the EDEM software is used to establish the alfalfa seed model and rest angle simulation model,and the Hertz-Mindlin no-slip contact model is used to conduct the Plackett-Burman test,the steepest climb test and the Box-Behnken test to obtain the best combination of contact parameters for alfalfa seeds in turn.2.The physical parameters of the coating powder are measured by physical tests,and the best combination of contact parameters for the coating powder is obtained by using the Hertz-Mindlin with JKR contact model and conducting the Plackett-Burman test,the steepest climb test and the Box-Behnken test in turn.The contact parameters between alfalfa seeds and coating powder are calibrated by combining physical and simulation tests,and the contact parameters are obtained by fitting the equations through quadratic regression.3.Theoretically,the mixing mechanism between seeds and powders is analyzed,and the coefficient of variation is used as the evaluation index to conduct a single-factor test to determine the range of working parameters for seed pellet coating;the Plackett-Burman test is conducted,and the working parameters that had significant effects on the response values are selected from the coating pot vibration frequency,coating pot vibration amplitude,coating pot vibration direction,coating pot rotation speed and coating pot tilt angle: coating pot tilt angle,coating pot rotation speed and coating pot vibration frequency.4.Based on the results of single-factor test and Plackett-Burman test,quadratic regression orthogonal tests are conducted with different coating parameters,and the best combination of coating parameters for alfalfa seeds is obtained as follows: coating pot speed of 58r/min,coating pot tilt angle of 34°,and coating pot vibration frequency of15Hz;single powder supply quantity,single liquid supply quantity and coating time as the test parameters,and the best combination of coating parameters for alfalfa seeds is obtained as follows The optimal parameters of alfalfa seed pellet coating were obtained as follows: the optimal value of single powder supply is 10 g,the optimal value of single liquid supply is 10 ml,and the optimal value of coating time is 5min.更多还原