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 multi-objective 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 16m/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.
作者
王立军
冯鑫
武振超
李瑞
崔友强
李义博
ANG Lijun;FENG Xin;WU Zhenchao;LI Rui;CUI Youqiang;LI Yibo(College of Engineering,Northeast Agricultural University,Harbin 150030,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2018年第10期115-123,共9页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51475090)
黑龙江省科学基金项目(E2017004)
国家重点研发计划项目(2018YFD0300103)
关键词
玉米联合收获机
清选装置
振动筛
阶梯缓冲带
maize harvester
cleaning device
vibrating screen
stepped buffer zone
