双出风口清选装置气流场仿真及清选试验研究

Simulation and test of airflow field of double outlet cleaning device

针对传统大豆联合收获机中单出风口清选装置存在含杂率和损失率较高等难题,采用CFD和CFDDEM耦合方法对比分析清选装置气流分布和物料筛分过程,选取振动筛曲柄转速、振动筛振幅和风机转速为试验因素,开展台架单因素和响应面试验。仿真试验结果表明,双出风口清选装置筛前位置气流速度较大,整体气流分布情况理想,筛分效率高。台架试验结果表明,所选试验因素对试验结果均有显著影响,当振动筛曲柄转速增加时,含杂率先降后升,损失率上升;当振动筛振幅增加时,含杂率下降,损失率上升;当风机转速增加时,含杂率下降,损失率上升。响应面试验结果表明,当振动筛曲柄转速为375 r·min^(-1)、振动筛振幅为11.2 mm、风机转速为1263 r·min^(-1)时,清选效果最佳,损失率和含杂率分别为0.38%、0.30%。

Aiming at the problems of high impurity and loss rate in the cleaning unit of single outlet in traditional soybean combine harvester,the air distribution and material screening process of the cleaning unit were compared and analyzed by CFD and CFD-DEM coupling methods.Then,the rotating speed of vibrating screen,amplitude and fan speed were selected as test factors to conduct bench single factor test and response surface test.The simulation results showed that the air velocity in front of the screen was higher,the overall air distribution was better,and the screening efficiency was higher.The bench test results showed that the selected test factors had significant effects on the test results.When the rotating speed of the vibrating screen increased,the impurities first decreased and then increased,and the loss rate increased.When the amplitude increased,the impurity rate decreased and the loss rate increased.When the fan speed increased,the impurity content decreased and the loss rate increased.The response surface test results showed that when the vibrating screen speed was 375 r·min^(-1),the amplitude was 11.2 mm,and the fan speed was 1263 r·min^(-1),the cleaning effect was the best,and the loss rate and impurity rate were 0.38%and 0.30%,respectively.