基于CFD-DEM的胡麻风筛式清选装置仿真分析与试验

为阐明胡麻脱粒物料在振动筛上实际的筛分效果，采用CFD-DEM耦合方法，对胡麻脱粒物料在胡麻联合收获机风筛式清选装置中的清选效果进行研究，探究鱼鳞筛开口角度、气流速度、清选筛振动频率以及清选筛振幅对清选效果的影响，并通过统计胡麻籽粒含杂率和清选损失率来衡量不同工作参数下分离清选装置的工作性能。仿真试验结果表明：鱼鳞筛开口角度最优为30°，鱼鳞筛透筛率为79.77%，茎秆透筛率为65.52%，籽粒透筛率为90.01%；振动筛振动幅度最优为15 mm，胡麻籽粒损失率为3.6%，籽粒含杂率为3.4%；振动筛振动频率最优为6 Hz，清选损失率为3.5%，籽粒含杂率为3.4%；风机风速最优为5.5 m·s^-1，籽粒含杂率为3.2%，清选损失率为3.0%。结合优化工作参数进行大田作业性能验证试验，通过对机收后的收集物料测定试验指标可知，总清选损失率为3.58%，籽粒含杂率为3.16%，大田试验结果与仿真模拟结果基本一致。机收后的胡麻籽粒外形完整，破损现象较少，含杂率与总损失率均达到相关试验标准要求，表明优化后的参数满足胡麻联合收获标准要求。

Simulated analysis and test of air\|screen cleaning device for flax based on CFD-DEM coupling

In order to study the real screening effect of flax threshing materials on the vibrating screen, the CFD-DEM coupling method was used in this study to examine the cleaning effects of flax threshing materials in the air and screen cleaning device of the flax combine harvester and to explore the influence of the opening angle of the scale screen, the air velocity, the vibration frequency of the cleaning screen and the amplitude of the cleaning screen on the cleaning effect to measure the working performance of the separation and cleaning device under different working parameters. The simulation test results showed that the optimal opening angle of the chaffer was 30°, the sieving rate of the chaffer was 79.77%, the sieving rate of the stem was 65.52%, and the sieving rate of the grain was 90.01%. The optimum vibrating amplitude of the vibrating screen was 15 mm, the loss rate of flax seed was 3.6%, and the impurity content of flax seed was 3.4%. The optimum vibrating frequency of the vibrating screen was 6 Hz, the cleaning loss rate was 3.5%, and the impurity content of the grain was 3.4%. The optimal wind speed of the fan was 5.5 m·s^-1, the grain impurity content was 3.2%, and the cleaning loss rate was 3.0%. The field operation performance verification test was carried out based on the optimized working parameters. According to the test indicators of the collected materials after the machine harvest, the total cleaning loss rate was 3.58%, and the grain impurity content rate was 3.16%. The field test results were basically consistent with the simulation results. After mechanical harvesting, the shape of flax seeds was complete, the damage phenomenon was less, and the impurity content and total loss rate met the requirements of relevant test standards. The results showed that the optimized parameters met the requirements of flax combined harvesting standards.