Authors

Abstract

To address the problems of high kernel breakage rate and high unthreshed rate during direct maize kernel harvesting under conditions of high moisture content and dense planting - common in the single longitudinal axial-flow harvesters widely used in Southwest China - a tangential–transverse axial-flow double-drum maize threshing device was designed and optimized. The drum combination configuration was determined through theoretical analysis, and the influence of the vertical spacing between the two drums on threshing performance was investigated. The flexible concave screen and transition sieve plate were also redesigned. Using EDEM and Adams software, the threshing process was simulated and analysed to verify the rationality of the design. A prototype was fabricated, and drum speed, deflection angle, and feeding rate were selected as test factors. A response surface experiment was conducted with kernel breakage rate and unthreshed rate as evaluation indices. Multi-objective optimization of the regression model was performed using the response surface methodology (RSM). After rounding, the optimal parameter combination was determined as follows: drum speed of 453 r/min, deflection angle of 69°, and feeding rate of 6.7 kg/s. Verification tests yielded a kernel breakage rate of 2.76% and an unthreshed rate of 0.11%, meeting production requirements and providing a valuable reference for the design of maize threshing devices in Southwest China.

Abstract in Chinese

针对西南地区普遍应用的单纵轴流机型在高含水率密植条件下玉米籽粒直收存在的破碎较高、未脱净率较高问题，设计切流-横轴流双滚筒玉米脱粒装置并进行优化设计，通过理论分析确定滚筒的组合方式，研究两滚筒间垂直高度对脱粒的影响，并对柔性凹板筛、过渡筛板进行重新设计，采用EDEM、Adams对脱粒过程进行仿真分析验证设计的合理性。搭建样机，选取滚筒转速、导流角、喂入量为试验因素，以破碎率和未脱净率为试验指标开展响应面试验，基于响应曲面法对回归模型进行多目标优化，得到最优参数圆整后的组合为：滚筒转速453r/min、导流角为69°、喂入量为6.7kg/s，验证试验测得玉米破碎率2.76%，未脱净率为0.11%，满足生产需求，可为西南地区的脱粒装置设计提供参考。