油菜收获清选筛面物料匀散导流装置设计与试验

Design and Experiments of Material Uniform Dispersion and Diversion Device on Cleaning Screen Surface for Oilseed Harvesting

针对长江流域油菜主产区普遍使用的履带式油菜联合收获机进行高密高产油菜收获时清选筛面脱出物易堆积,影响油菜籽粒透筛,导致清选损失率高和作业效率低的问题,通过分析清选过程中物料抛散运动规律,设计了筛面物料匀散导流装置,确定了影响清选系统作业性能的装置关键结构与作业参数。构建了清选系统CFD-DEM耦合仿真分析模型,采用二次回归正交组合试验方法,探究了导流杆摆动频率、导流杆转速、驱动关节滑槽倾角对清选损失率、清选含杂率的影响,确定了最优参数组合。仿真试验结果表明,各因素对损失率和含杂率均具有显著影响,其中以导流杆摆动频率影响最显著,最优参数组合为导流杆摆动频率12.5 Hz、导流杆转速120 r/min、滑槽倾角20°。基于优化后的参数进行台架试验,结果表明,在相同的大喂入量条件下,增设筛面匀散导流装置后清选损失率为3.97%,含杂率3.71%,对比原清选系统损失率降低49.8%,含杂率降低34.7%,能够满足高密高产油菜的低损高效清选作业要求。

To solve the problem that the threshed outputs on the sieve surface of the crawler-type rape combine harvester commonly used in the main oilseed rape producing areas in the Yangtze River basin is prone to accumulation and stagnation when harvesting high-density and high-yield rape, which affects the penetration of oilseeds through the sieve and leads to a high loss rate and low operating efficiency, an uniform dispersion diversion device for material movement on the sieve surface was designed by analyzing the material dispersion movement law during the cleaning process, and the key operating and structural parameters of the device that affect the operating performance of the cleaning system were determined. Based on the coupling method of CFD-DEM, a quadratic regression orthogonal combination test method was used to carry out parameter combination simulation optimization test with oscillation frequency of diversion rod, rotation speed of diversion rod and drive joint chute inclination angle as test factors, and cleaning loss rate and cleaning impurity rate as performance evaluation indexes. The results showed that each factor had a significant effect on the performance evaluation index, among which the most significant effect was on the oscillation frequency of diversion rod. The optimal combination of parameters was oscillation frequency as 12.5 Hz, rotation speed as 120 r/min, and chute inclination angle as 20°. Based on the optimized parameters, the results of the bench test showed that under the same high feeding condition, the cleaning loss rate after the configuration of the device was 3.97%, which was 49.8% lower than that of the original cleaning system, and the impurity rate was 3.71%, which was 34.7% lower. The results showed that the optimal cleaning system could meet the requirements of the crawler combine harvester for the low-loss and high-efficiency cleaning operation of high-density and high-yield rape. The research results can provide reference for the design and improvement of cleaning system for oilseed harvesting.