Authors

Abstract

A discrete element model (DEM) of rapeseed threshing and separation was established based on EDEM software. The simulation results were compared with bench test data, showing an absolute error of 0.33% and a relative error of 55% for threshing loss. The relative errors for the proportion of threshed material on the sieve surface and the left–right distribution ratio of threshed material on the sieve surface were 1.21% and 2.38%, respectively, verifying the accuracy of the simulation model. Secondly, a three-factor, three-level Box–Behnken experimental design was conducted, with threshing drum speed, guide plate angle, and threshing gap as test factors, and threshing loss, proportion of threshed material on the sieve surface, and left–right distribution ratio of the threshed material as evaluation indicators. The influence of each factor on the evaluation indicators was analyzed, and regression models between the test factors and evaluation indicators were established. Through a multi-objective optimization solution, combined with consideration of the actual operating conditions and processing requirements of the rapeseed combine harvester, the optimal parameter combination was determined as: drum speed of 550 r/min, guide plate angle of 75°, and threshing gap of 8 mm. Finally, a prototype was developed based on the optimized structure and operating parameters, and its rapeseed harvesting performance was tested by a third-party inspection agency. Field tests showed a total harvest loss rate of 5.6%, impurity rate of 2.3%, breakage rate of 0.4%, and an operational productivity of 0.57 hm²/h. The performance exceeded the requirements of industry standards. This study provides a valuable reference for the performance optimization of threshing devices.

Abstract in Chinese

基于EDEM软件构建了油菜脱粒分离离散元模型，仿真结果和台架对比试验表明，脱粒损失绝对误差为0.33%，相对误差为55%，筛面脱出物占比和筛面脱出物左右比值的相对误差分别为1.21%和2.38%，验证了仿真模型的准确新。以脱粒滚筒转速、导草板角度和脱粒间隙为试验因素，以脱粒损失、筛面脱出物占比和筛面脱出物左右分布比值为评价指标，开展了三因素三水平Box-Behnken试验，分析了各因素对评价指标的影响关系，建立了试验因素与评价指标之间的回归数学模型，通过多目标优化求解，结合油菜联合收割机实际工况和加工要求，确定优化后的参参数组合为：滚筒转速550 r/min，导草板角度75°，脱粒间隙8 mm。在最优结构和工作参数下，试制了样机并委托第三方检测机构对油菜收获作业性能进行了检测，田间实测收获总损失率5.6%、含杂率2.3%、破碎率0.4%，作业小时生产率0.57hm2/h，作业性能优于行业标准要求。该研究可为脱粒装置性能优化提供参考。