油菜联合收获机凸块扰流式旋风分离清选装置研究

针对油菜联合收获机旋风分离清选气流场分布存在死区,导致油菜脱出物分离不彻底,夹带损失率增加、清洁率降低等问题,提出了一种凸块扰流式旋风分离清选装置,通过旋风分离筒下锥段内壁螺旋间隔排列的圆柱磁块形成柱状凸起,扰动内部气流场。基于运动学与动力学分析开展了旋风分离气流场死区对油菜籽粒迁移的影响,分析表明气流场死区不利于杂余的分离;明确了凸块螺旋间隔排布方式,以旋风分离筒入口风速和吸杂口风速以及凸块排列的螺旋升角、间距、螺旋头数为试验因素,以清选装置清洁率、损失率为评价指标,基于自主研发的油菜联合收获关键部件试验台开展了单因素试验与Box-Behnken试验,建立了清洁率与损失率和影响因素之间的数学关系模型,得出了旋风分离清选装置最佳参数组合并开展了台架和田间验证试验。单因素试验结果表明,增加凸块扰流可提升旋风分离清选装置性能,当凸块采用4头均匀对称螺旋排布时,籽粒损失较少且清洁率较高;Box-Behnken试验结果表明,最佳参数组合为螺旋升角66.2°、凸块间距48.3 mm、入口风速4.9 m/s、吸杂口风速25.4 m/s,在最佳参数组合下,清洁率与损失率的预测值分别为94.71%和3...

Design and Experiment of Cyclone Separation Cleaning Device with Raised Cylinder Disturbing Airflow Field for Rapeseed Combine Harvest

Existing cyclone separation cleaning device, which uses the suspending airflow to separate rapeseed from the threshing outputs, still has the challenge to improve the performance, highlighting a need to reduce the airflow inside the cyclone separator for rapeseed combine harvest. As a solution, cyclone separation cleaning device with raised cylinder disturbing airflow field was put forward. The internal airflow field would be disturbed by raised cylinders that were spiral arranged in the inner wall of the lower cone of the cyclone separator. The effect of airflow dead zone on the migration of rapeseed was studied based on dynamics and kinematics analysis, and the kinematical equation indicated that the dead zone would not benefit the performance of the cleaning device. Besides, the arrangement of the raised cylinders was clarified. By taking the inlet and outlet velocities, spiral angle, space, and spiral number of the raised cylinders as the factor, while the cleaning ratio and loss ratio were considered to be the evaluation indexes, the single factor experiment and Box-Behnken experiments were carried out based on the self-developed test-bench for key components of rapeseed combine harvester. Furthermore, the mathematical model of the relationship between cleaning ratio, loss ratio and the factors were established to figure out the optimal parameter combination of the cleaning device. The single factor experiment results illustrated that the raised cylinders could help improve the performance of the cleaning device. The loss ratio was low and the cleaning ratio was relatively higher when the number of spirals was 4. Box-Behnken experiment results showed that the optimal parameter combination were the spiral angle of 66.2°, space between raised cylinders of 48.3mm, inlet velocity of 4.9m/s, and outlet velocity of 25.4m/s. Under the optimal condition, the predicted values of cleaning ratio and loss ratio were 94.71% and 3.58%, respectively. Meanwhile, the measured values of cleaning rate and loss rate, obtained by bench test, were 93.87% and 4.21%, respectively. The field experiment showed that the cyclone separation cleaning device operated smoothly in the field, and the cleaning ratio and loss ratio were 90.03%~92.78% and 4.52%~5.07%, respectively. The research result could provide a reference for the structural optimization and improvement of the cleaning device for the rapeseed combine harvester.