独立电驱清选的高湿小麦脱粒机设计与试验

Design and Test of Isolated-motor-driven Cleaning System for High Moisture Wheat Thresher

摘要:

针对以贵州为代表的丘陵山区小麦收获时含水率高，传统小麦脱粒机因动力不足难以有效实现高湿小麦清选分离的难题，本文提出一种独立电驱清选技术，以降低高湿小麦分段式收获清选含杂率与损失率。结合清选系统工作原理与空气动力学理论，开展籽粒运动过程分析，确定小麦清选性能关键影响因素。融合计算流体力学和离散元法（CFD-DEM）构建清选系统的流固耦合数值仿真模型，以含杂率、损失率为评价指标，探究导流管道倾斜角、吸杂管道横截面积与吸杂口负压对清选性能的影响规律。采用非支配排序遗传算法（NSGA-Ⅱ）开展关键参数匹配优化设计，当导流管道倾斜角为24.0088°、吸杂管道横截面积为179.8062cm2、吸杂口负压为873.6316Pa时，清选系统含杂率与损失率分别为0.92%和0.96%。试制样机并开展试验验证，结果表明，清选含杂率与损失率分别为1.21%和0.82%，对比传统小麦脱粒机，损失率基本保持不变，含杂率降低35.98%。研究成果可为丘陵山区高湿小麦清选系统装备研发提供理论与技术支撑。

Abstract:

Aiming at the high moisture content wheat harvested in hilly and mountainous areas represented by Guizhou, the traditional wheat thresher can not effectively realize the cleaning separation of high moisture wheat due to insufficient power. A isolated-motor-driven cleaning technology was proposed to reduce the impurity rate and loss rate for high moisture wheat cleaning in segmented harvesting. According to the working principle of the cleaning system and aerodynamic theory, the grain movement process was analyzed and the key factors influencing the wheat cleaning performance were identified. A numerical simulation model with fluid-solid coupling was constructed by integrating computational fluid dynamics and discrete element method (CFD-DEM). Taking the impurity rate and loss rate as the evaluation indexes, the influence of the tilting angle of guide tube, cross-sectional area of suction tube and negative pressure at the suction port on the cleaning performance was investigated. The non-dominated sorting genetic algorithm (NSGA-Ⅱ) was used to perform the optimization design of key parameters matching. When the tilting angle of guide pipe was 24.0088°, the cross-sectional area of suction pipe was 179.8062cm2, and the negative pressure at the suction port was 873.6316Pa, the impurity rate and loss rate of the cleaning system were 0.92% and 0.96%, respectively. Prototype trial manufacture and experimental verification was carried out, the results showed that the cleaning impurity rate and loss rate were 1.21% and 0.82%, respectively. Compared with the traditional wheat thresher, the impurity rate was reduced by 35.98% with the loss ratio remaining no large change. The research results can provide theoretical and technical support for the research and development of high moisture wheat cleaning equipment of hilly and mountainous areas.