Authors

Abstract

Aiming at the problems of high grain entrainment loss rate and impurity rate of traditional horizontal axial-flow combine harvesters, a horizontal axial-flow threshing-separating device with coaxial differential threshing drum, conical cleaning fan, double-layer vibrating screen and spiral plate-tooth re-thresher is designed. Meanwhile, a test-bed with a feeding rate of 2 kg/s is designed to improve the device performance. The test through quadratic orthogonal rotation combination design method is used to inspect the effects of the differential drumspeed combination, conical fan blade taper, and length ratio of the high and low speed sections of the differential drum on the loss rate, crushing rate , impurity rate and threshing power consumption. The regression mathematical models of the loss rate, crushing rate, impurity content and threshing power consumption are established, and the multi-objective optimization calculation of the regression mathematical model is carried out by using MATLAB optimization toolbox. The results show that the order of the three factors affecting the loss rate and impurity content of the horizontal axial-flow threshing-separating device is the differential drumspeed combination, the conical fan bladetaper, and the length ratio of high and low speed sections of the differential drum. The field test results show that the performance index of the horizontal axial-flow separation device is better than the requirements of the national standard.

Abstract in English

针对传统横轴流联合收获机籽粒夹带损失率和籽粒含杂率高的问题，设计了以同轴差速脱粒滚筒、圆锥形清选风机、双层振动筛和螺旋板齿式复脱器为主要工作部件的横轴流脱分选装置。为了提升横轴流脱分选装置工作性能，设计了喂入量为2 kg/s的试验台，采用二次正交旋转组合设计法进行工作性能试验，考察差速滚筒转速组合、圆锥形风机叶片锥度、差速滚筒高低速段长度配比3个因素对损失率、破碎率、含杂率和脱粒功耗4个性能指标的影响。建立了损失率、破碎率、含杂率、脱粒功耗的回归数学模型，利用Matlab优化工具箱对回归数学模型进行了多目标优化计算。结果表明：影响横轴流脱分选装置损失率、含杂率的3个因素主次顺序依次为差速滚筒转速组合、圆锥形风机叶片锥度、差速滚筒高低速段长度配比；影响横轴流脱分选装置破碎率、脱粒功耗的3个因素主次顺序依次为差速滚筒转速组合、差速滚筒高低速段长度配比、圆锥形风机叶片锥度；最优参数组合为：差速滚筒转速组合750/950 r/min，风机叶片锥度 3.8°，高速段比例30％；对应工作性能指标为：损失率1.57%、破碎率0.71%、含杂率0.38％，脱粒功耗6.67 kW/kg。田间试验结果表明，横轴流脱分选装置工作性能指标优于国家标准规定要求。