油菜联合收获后含杂油菜籽复清机设计与试验

Design and Experiment on Re-cleaning Machine for Rapeseed after Combine Harvesting

针对现有油菜联合收获机收获作业时油菜籽粒细小不易分离导致收获后籽粒含杂率高、人工复清劳动强度大、缺乏晾晒前机械化复清装备的生产实际问题,设计了一种适于油菜联合收获机作业后含杂油菜籽的复清机。通过运动学和动力学分析确定了螺旋输送装置、离心振动式筛分装置和侧向风选装置的结构及其运行参数,解析了离心振动式筛分装置离心过程和振动过程,基于CFD分析了清选罩壳内部气流场状态。以振动频率、垂直振幅和离心风机出风口风速为影响因素,以油菜联合收获后含杂油菜籽复清机籽粒含杂率和筛分效率为评价指标,开展了单因素试验与正交试验,确定了较优运行参数组合。单因素试验结果表明:振动频率在12.08~14.61 Hz,垂直振幅在3.59~3.64 mm,离心风机出风口风速在5~7 m/s范围内时,清选性能较优;正交试验结果表明:影响含杂率因素主次为离心风机出风口风速、振动频率、垂直振幅,影响筛分效率因素主次为振动频率、垂直振幅、离心风机出风口风速,确定较优参数组合:振动频率为14.61 Hz、垂直振幅为3.61 mm、离心风机出风口风速为7 m/s,在此参数组合下,油菜联合收获后含杂油菜籽复清机的籽粒含杂率平均值为0.53%,筛分效率平均值为98.39%,符合油菜籽粒后续存储标准(含杂率小于3%)。

After conventional combine harvesting,high impurity rate and large labor consumption due to the small size of rapeseed that makes the seed hard to be separated,are still the problems that remained to be solved,highlighting the necessity of the mechanized re-cleaning equipment before the drying process.As a solution,a re-cleaning machine for rapeseed after combine harvesting was put forward.Systematically,the structure and operating parameters of the key components,including the screw conveyor device,centrifugal-vibrating screening device and lateral air separation device,were determined by kinematics and dynamic analyses.Furthermore,the centrifugal motion and vibration motion of the centrifugal-vibrating screening device were also analyzed.Based on CFD,the status of the airflow field inside the shell of the lateral air separation device was figured out.Finally,a single factor experiment and an orthogonal combination experiment were carried out to determine the optimal combination of operating parameters by taking the vibration frequency,vertical amplitude,and air velocity of fan outlet as influencing factors,and considering the impurity rate and screening efficiency as evaluation indexes.The results of the single factor experiment indicated that the cleaning performance was better when the vibration frequency,vertical amplitude,and air velocity of the fan outlet were in the ranges of 12.08~14.61 Hz,3.59~3.64 mm,and 5~7 m/s,respectively.What’s more,the results of the orthogonal experiment illustrated that the primary and secondary factors affecting the impurity rate were the air velocity of the fan outlet,vibration frequency,and vertical amplitude.Meanwhile,the primary and secondary factors affecting the screening efficiency were the vibration frequency,vertical amplitude,and air velocity of fan outlet.The optimal parameter combination was obtained when the vibration frequency,vertical amplitude,and the air velocity of fan outlet were 14.61 Hz,3.61 mm,and 7 m/s,respectively.Under optimal parameter combination conditions,the average impurity rate was 0.53%which met the requirement of subsequent storage of rapeseeds(impurity rate was lower than 3%),and the screening efficiency could achieve 98.39%.The research result can provide a reference for the structural improvement and optimal design of the screening device for rapeseed.