针对横置轴流滚筒长度受限和脱出物在清选筛入口一角堆积严重的问题,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置差速轴流式脱分选系统。为了提升横置差速轴流脱分选系统工作性能,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:影响横置差速轴流脱分选系统损失率、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;影响横置差速轴流脱分选系统破碎率、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、850 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 k W/kg。田间试验结果表明,横置差速轴流脱分选系统工作性能指标优于行业标准。
The discrete element method was utilized to construct three-dimensional discrete element models for the rice mixture,and their motions were analyzed numerically on a planar vibration screening device.The results showed that,after falling onto the vibrating screen surface,the mixture undergoes a reciprocating motion within the same cycle.During the screening process,the mixture undergoes segregation,slides along the screen surface,passes through the screen and then falls.In comparing the movement of grains and shriveled grains,it can be seen that the velocity of shriveled grains experiences cyclical changes,which is consistent with the grains’motion cycle.The impact on grains is shown to be greater than that on shriveled grains,and the average speeds of shriveled grains and grains converge.The curve shows that the screening of repetitive movements has a significant effect on the average velocity of shriveled grains,but also the velocity of shriveled grains and the vibration parameters can be well represented by a fitting equation.It is beneficial for the separation of grains from shriveled grains to choose a greater vibration frequency and screen surface inclination in the range of commonly used.
Li HuaWang JinshuangYuan JianboYin WenqingWang ZhimingQian Youzhang
