基于EDEM的小麦精量排种器设计与试验

为实现小麦的精量排种,设计了一种精量小麦排种器。对排种器进行设计计算,最终确定排种器为锥盘式,型孔数量为50个,锥角为30°。采用EDEM软件进行仿真分析,结果显示:当转盘转动速度为19.38r/min、型孔长度平均值为7.95mm、小麦种子外层厚度为8.20mm时,作业合格率为89.55%,单粒率可达到50.80%,符合排种器的作业要求。试验结果表明:排种器具有行间的排量较足和一致性好的特质,在小麦的播种过程中,系数的变异已经控制在10%以内。根据测量的秧苗数量计算面积,小麦每667m 2可达到4万株,分蘖的数量为3~10株,分蘖完成后每667m 2达25万株,可以满足小麦种植的实际需求。

Design and Experiment of Wheat Precision Metering Device Based on EDEM

Based on the scientific concept of sucking seeds under negative pressure and throwing seeds under positive pressure,combining with accurate metering methods,and taking advantage of the great differences of wheat products,this paper has created a kind of metering equipment with seed guide strips in the metering tray.Under this background,the concept of dual-purpose pneumatic precision metering system and design for wheat has been deeply studied.The three-axis size of wheat determines the volume of the seed guide strip in the metering tray:a rectangular structure with a length of 6 mm,a width of 2 mm and a height of 2 mm,and an arrangement of"I"shape,with a tilt angle of about 65 degrees.According to the grain size of wheat to determine the actual parameters needed by the metering device,the main parameters need to be determined are:negative pressure value and airflow speed,as well as the rotation speed of the metering device.The minimum seed suction negative pressure of wheat is 1950Pa,the local flow rate is 0.068m/s,the actual air flow demand of metering device is 1.40 x 10-6m3/s,and the velocity of the hole should be kept below 0.30m/s.The software EDEM is used to transfer seeds to the inside of the metering device in the seed box.This process has the actual analysis of simulation.It shows the relationship between the grain gold and the group velocity and displacement of the crop.The simulation results are analyzed and compared with the recorded images.The results are very consistent.The final result shows that the metering device has the characteristics of sufficient row displacement and good consistency,and the variation of coefficient has been controlled within 10%in the process of wheat seeding.According to the number of seedlings measured to calculate the area,the state of wheat can reach 40,000 plants per mu,the number of tillers is about 3 to 10 plants,after the completion of tillering,about 250,000 plants per mu,which can meet the actual demand of millet planting.