摘要
为降低筛分作业后籽粒损失率,同时保证籽粒清洁率,分析了玉米脱出物在气流场中运动状态,基于贝壳筛设计阶梯式筛体,并通过籽粒碰撞理论设计阶梯缓冲带,使籽粒在阶梯暂时"滞留",减轻杂余对籽粒夹带作用。在筛面振幅19 mm条件下,采用CFD-DEM耦合仿真方法,以入风口气流速度、气流角、阶梯高度和筛面振动频率为试验因素,玉米籽粒清洁率和损失率为试验指标,进行二次正交旋转组合试验。通过响应曲面方法对试验结果进行分析,利用软件对回归数学模型进行优化。结果表明:当气流速度、气流角、阶梯高度和振动频率分别为16 m/s、25°、8.36 mm和4.45 Hz时,籽粒损失率和清洁率分别为1.69%和98.8%,通过贯流风阶梯式振动筛台架试验验证了结果的准确性。通过对比试验得到,阶梯式贝壳筛作业后籽粒损失率降低为2.12%,清洁率提高到99.16%,清选性能得到提高。
To reduce the loss of maize and ensure certain cleanliness of maize after screening operations,the movement of maize mixture was analyzed in the airflow field,and the stepped screen body was designed based on shell screen. The stepped buffer zone was designed by analyzing the theory of maize's collision to temporarily retain grains in the stepper and reduce the effect on carrying maize from maize mixture and avoid maize accumulation in the ladder. However,maize debris directly went across the ladder. To make the screen amplitude as 19 mm,the computational fluid dynamics and discrete element method(CFD-DEM) were coupled in the quadratic orthogonal rotational-combinational simulation tests.The factors were the inlet velocity and direction angle of airflow,height of the ladder and vibration frequency of screen. The indexes were the loss and cleanliness of maize grains collected. The test data were analyzed by the response surface method and the regression mathematical models were multiobjective optimized by using Design-Expert software. The results showed that the loss and cleanliness of maize were 1. 69% and 98. 8%,respectively,when the inlet velocity of airflow was 16 m/s,the direction angle of airflow was 25°,the height of the ladder was 8. 36 mm,and the vibration frequency of screen was 4. 45 Hz. The performances met the requirements of corn harvest. The performance tests were done in the laboratory to verify the accuracy of the simulation results. The rate of maize loss was 2. 12% and the cleanliness of maize grains collected was 99. 16% after screening. Compared with the flat shell screen,the loss of maize grains across the stepped shell screen was reduced by 1. 14 percentage points and the cleanliness of maize grains was increased by 1. 98 percentage points. The cleaning performance of screen was improved.
引文
1柴宗文,王克如,郭银巧,等.玉米机械粒收质量现状及其与含水率的关系[J].中国农业科学,2017,50(11):2036-2043.CHAI Zongwen,WANG Keru,GUO Yinqiao,et al.Current status of maize mechanical grain harvesting and its relationship with grain moisture content[J].China Agricultural Sciences,2017,50(11):2036-2043.(in Chinese)
2王成军,李耀明,马履中.3自由度混联振动筛设计[J].农业机械学报,2011,42(增刊):69-73.WANG Chengjun,LI Yaoming,MA Lüzhong.Design of three degree of freedom hybrid vibration screen[J].Transactions of the Chinese Society for Agricultural Machinery,2011,42(Supp.):69-73.(in Chinese)
3郝俊发,韩增德,刘贵明,等.玉米脱粒机清选装置的研究现状及发展趋势[J].安徽农业科学,2016,44(5):322-324,330.HAO Junfa,HAN Zengde,LIU Guiming,et al.Research status and development trend of cleaning device of corn thresher[J].Journal of Anhui Agricultural Sciences,2016,44(5):322-324,330.(in Chinese)
4任述光,谢方平,王修善,等.4LZ-0.8型水稻联合收割机清选装置气固两相分离作业机理[J].农业工程学报,2015,31(12):16-22.REN Shuguang,XIE Fangping,WANG Xiushan,et al.Gas-solid two-phase separation operation mechanism for 4LZ-0.8 rice combine harvester cleaning devic[J].Transactions of the CSAE,2015,31(12):16-22.(in Chinese)
5张敏,金诚谦,梁苏宁,等.风筛选式油菜联合收割机清选机构参数优化与试验[J].农业工程学报,2015,31(24):8-15.ZHANG Min,JIN Chengqian,LIANG Suning,et al.Parameter optimization and experiment on air-screen cleaning device of rapeseed combine harvester[J].Transactions of the CSAE,2015,31(24):8-15.(in Chinese)
6李菊,王增彪,沈惠平,等.凸柱筛面并联振动筛的谷物筛分试验与分析[J].机械设计与研究,2016,32(1):150-154,158.LI Jü,WANG Zengbiao,SHEN Huiping,et al.Experiment and analysis of parallel vibrating sieve with convex column screen surface on grain screen[J].Machine Design and Research,2016,32(1):150-154,158.(in Chinese)
7杜家林.复合结构条形筛面与铸造筛面[J].矿山机械,1990(11):39-41.
8马征,李耀明,徐立章.仿生非光滑筛面近筛层微观气流场研究[J].农业机械学报,2011,42(增刊):74-77,9.MA Zheng,LI Yaoming,XU Lizhang.Micro flow field on adjacent screen of bionic nonsmooth cleaning screen[J].Transactions of the Chinese Society for Agricultural Machinery,2011,42(Supp.):74-77,9.(in Chinese)
9 DONG K J,YU A B.Numerical simulation of the particle flow and sieving behavior on sieve bend/low head screen combination[J].Minerals Engineering,2012,31:2-9.
10王立军,张传根,丁振军.玉米收获机清选筛体结构优化[J/OL].农业机械学报,2016,47(9):108-114.http:∥www.jcsam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=20160916&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2016.09.016.WANG Lijun,ZHANG Chuangen,DING Zhenjun.Structure optimization of cleaning screen for maize harvester[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2016,47(9):108-114.(in Chinese)
11韩丹丹,张东兴,杨丽,等.基于EDEM-CFD耦合的内充气吹式排种器优化与试验[J/OL].农业机械学报,2017,48(11):43-51.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=20171106&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2017.11.006.HAN Dandan,ZHANG Dongxing,YANG Li,et al.Optimization and experiment of inside-filling air-blowing seed metering device based on EDEM-CFD[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2017,48(11):43-51.(in Chinese)
12马秋成,雷林韬,卢安舸,等.基于CFD-DEM耦合法的莲子壳仁分离装置优化与试验分析[J].食品与机械,2016,32(12):87-91.MA Qiucheng,LEI Lintao,LU Ange,et al.Simulation optimization and test of pneumatic separating device for lotus seed shell and kernel base[J].Food&Machinery,2016,32(12):87-91.(in Chinese)
13蒋恩臣,孙占峰,潘志洋,等.基于CFD-DEM收获机分离室内谷物运动模拟与试验[J/OL].农业机械学报,2014,45(4):117-122.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=20140418&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2014.04.018.JIANG Enchen,SUN Zhanfeng,PAN Zhiyang,et al.Numerical simulation based on CFD-DEM and experiment of grain moving laws in inertia separation chamber[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2014,45(4):117-122.(in Chinese)
14刘兴博,叶彤,杨金砖.籽粒玉米收获机脱出物空气动力学特性分析及清选方法[J].农机使用与维修,2014(7):17-18.
15周文秀.玉米籽粒的物理力学特性研究[D].哈尔滨:东北农业大学,2015.ZHOU Wenxiu.The physical and mechanical properties research of corn grain[D].Harbin:Northeast Agricultural University,2015.(in Chinese)
16王立军,李洋,梁昌,等.贯流风筛清选装置内玉米脱出物运动规律研究[J/OL].农业机械学报,2015,46(9):122-127.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=20150918&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2015.09.018.WANG Lijun,LI Yang,LIANG Chang,et al.Motion law of maize mixture in cross air-and-screen cleaning device[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2015,46(9):122-127.(in Chinese)
17潘丽军,陈锦权.试验设计与数据处理[M].南京:东南大学出版社,2008.
18吕金庆,王英博,李紫辉,等.加装导流板的舀勺式马铃薯播种机排种器性能分析与试验[J].农业工程学报,2017,33(9):19-28.LJinqing,WANG Yingbo,LI Zihui,et al.Performance analysis and experiment of cup-belt type potato seed-metering device with flow deflector[J].Transactions of the CSAE,2017,33(9):19-28.(in Chinese)
19李洪昌,李耀明,唐忠,等.风筛式清选装置振动筛上物料运动CFD-DEM数值模拟[J/OL].农业机械学报,2012,43(2):79-84.http:∥www.j-csam.org/jcsam/ch/reader/view_abstract.aspx?flag=1&file_no=20120217&journal_id=jcsam.DOI:10.6041/j.issn.1000-1298.2012.02.017.LI Hongchang,LI Yaoming,TANG Zhong,et al.Numerical simulation of material motion on vibrating screen of air-and-screen cleaning device based[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2012,43(2):79-84.(in Chinese)
20杜小强,肖梦华,胡小钦,等.贯流式谷物清选装置气固两相流数值模拟与试验[J].农业工程学报,2014,30(3):27-34.DU Xiaoqiang,XIAO Menghua,HU Xiaoqin,et al.Numerical simulation and experiment of gas-solid two-phase flow in crossflow grain cleaning device[J].Transactions of the CSAE,2014,30(3):27-34.(in Chinese)