PDF《2019年5月》

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9 年5月农业机械学报第50 卷第5期doi:10.

6041 / j. issn. 1000鄄1298. 2019. 05.

006 基于 DEM CFD 的玉米气吸式排种器种盘设计与试验 丁摇 力1,2 摇 杨摇 丽1,2 摇 张东兴1,2 摇 崔摇 涛1,2 摇 高筱钧1,2 (1. 中国农业大学工学院, 北京 100083;

2. 农业农村部土壤 机器 植物系统技术重点实验室, 北京 100083) 摘要: 针对玉米气吸式排种器高速作业下种子运动十分复杂、难以进行准确分析计算的问题,采用 DEM(离散元) 和CFD(计算流体力学)耦合的方法,模拟了气吸式排种器工作过程,分析了种子受到的曳力和运动速度,得出不同 种子充种能力大小依次为:小扁形、类圆形、大扁形. 经过仿真分析,有针对性地选取不易吸附充种的大扁形种子, 建立充种过程数学模型,优化种盘型孔凸台高度和型孔凸台角度参数. 为了获得排种器的最佳性能参数,以型孔 凸台角度、型孔凸台高度、种层高度为试验因素,以排种合格指数、重播指数、漏播指数为试验指标进行三因素二次 旋转正交组合试验,并应用 Design鄄Expert 8郾 0郾

6 软件对试验数据进行多元回归分析和响应曲面分析,得到了各因素 对指标影响关系. 采用多目标优化方法,确定了最佳参数组合: 型孔凸台角度为 35郾76毅,型孔凸台高度为 3郾11 mm,种层高度为 55郾61 mm,排种合格指数最高. 此时,排种器性能指标为: 合格指数 91郾60% ,漏播指数 3郾90% ,重播指数 4郾50% . 对优化结果进行验证试验,并与原排种器进行对比,验证结果与优化结果基本一致,且 合格指数和漏播指数均优于原排种器,满足玉米精密播种的要求. 关键词: 玉米;

气吸式排种器;

离散元;

计算流体力学;

响应面法;

回归分析 中图分类号: S223郾2文献标识码: A 文章编号: 1000鄄1298(2019)05鄄0050鄄11 收稿日期:

2018 11 07摇 修回日期:

2019 01

02 基金项目: 国家重点研发计划项目(2017YFD0700703)、国家自然科学基金项目(51575515)和国家玉米产业技术体系建设项目(CARS 02) 作者简介: 丁力(1989―),男,博士生,主要从事农业机械装备设计与理论研究,E鄄mail: 604295294@ qq. com 通信作者: 杨丽(1975―),女,教授,博士生导师,主要从事农业机械装备及其智能化研究,E鄄mail: yangli@ cau. edu. cn Design and Experiment of Seed Plate of Corn Air Suction Seed Metering Device Based on DEM CFD DING Li1,2 摇YANG Li1,2 摇ZHANG Dongxing1,2 摇CUI Tao1,2 摇GAO Xiaojun1,2 (1. College of Engineering, China Agricultural University, Beijing 100083, China 2. Key Laboratory of Soil Machine Plant System Technology, Ministry of Agriculture and Rural Affairs, Beijing 100083, China) Abstract: The seeds movement under the high鄄speed operation condition of corn air suction metering device is very complicate, and it is difficult to carry out accurate analysis and calculation. The discrete element ( DEM) and computational fluid dynamics ( CFD) coupling method was used to accurately simulate the working process of air suction metering device, the bonding model of Zhengdan

958 corn seed cohesive particles was established, the airway structured grid was divided, and the related parameters were set up. The coupling simulation of EDEM and CFD was realized. Through simulation, the working process of the air suction metering device was accurately simulated, and the drag force and movement speed of the seeds were accurately analyzed. It was concluded that the seed filling ability of different seeds from big to small was as follows: small flat shape, round shape and big flat shape. In order to improve the operation quality of seed metering device and ensure the adaptability of seed metering device to seeds, the optimum design of seed plate structure for big flat shape was studied. The mathematical model of filling process was established to optimize the height of the plate type hole embossment and the angle parameter of the type hole embossment. Because of the complex movement caused by the interaction between seed populations and the interaction between seed populations and metering devices when the metering plate was rotated, further analysis and determination of the optimum angle were needed. In order to obtain the best performance parameters of the seed metering device, the angle of the type hole embossment, the height of the type hole embossment and the height of the seed layer were taken as the test factors, and the three factors of the seeding qualified index, multiple index and missing index were used as test indicators. Performing a three鄄factor quadratic rotation orthogonal combination test, the Design鄄Expert 8郾 0郾

6 software was used to analyze the test data by multiple regression analysis and response surface analysis. The primary and secondary factors affecting the qualified index and multiple index were obtained as follows: the height of type hole embossment, the height of seed layer and the angle of type hole embossment. The primary and secondary factors that affecting the missing index were the height of type hole embossment, the angle of type hole embossment and the height of seed layer. Using multi鄄objective optimization method, the optimum combination of parameters was determined as follows: the angle of type hole embossment was 35郾76毅, the height of type hole embossment was 3郾11 mm, the height of seed layer was 55郾61 mm, and the qualified index of seed metering was the highest. Under this condition, the qualified index of seed metering device was 91郾60% , the missing index was 3郾90% , and the multiple index was 4郾50% . The validation test of the optimization results was carried out. When the operating speed was

14 km/ h and the wind pressure was -

3 kPa, the qualified index was 91郾90% , the missing index was 3郾89% , and the multiple index was 4郾21% . The validation results were basically consistent with the optimization results, compared with the first鄄generation seed metering device, the qualified index and missing index were better. It can ensure the precision seeding of corn. Key words: corn;

air suction seed metering device;

discrete element;

computational fluid dynamics;

response surface method;

regression analysis 0摇 引言 玉米作为我国第一大粮食作........