| Corn and soybean are important food crops in China,which are of great signi ficance in food security.With the improvement of agricultural technology and yield,precision seeding technology has been widely used.Precision seeding is an important link to ensure the yield of corn and soybean.Precision seeding technology not only reduces the labor pressure of sowers,but also reduces the waste of seeds and greatly increases the yield of crops.At present,intercropping or intercropping is preferred in order to increase yields and save land resources.In order to adapt to the agronomic requirements of intercropping mode,when sowing different crops,it is usually necessary to use different seeder or change different seed tray,which not only increases labor intensity,but also increases production cost.Therefore,in order to solve the above problems,this study designed a pneumatic precision seed metering device for corn and soybean,which can not only reduce labor intensity,but also improve seeding accuracy.(1)Firstly,we selected three kinds of corn and soybean seeds common in Jilin and measured their physical characteristics,including three-dimensional size,1000-grain weight,density,water content,dynamic friction coefficient and static friction coefficient of seeds.(2)According to the physical and mechanical properties of corn and soybean,the seed tray,brush,air chamber and other parts of the seed metering device were designed.Among them,the design of seed tray hole is emphasized to meet the requirements of corn and soybean common seed row.Then we analyzed the four working processes of seed filling,seed cleaning,seed carrying and seed arrangement theoretically.(3)Using the coupling of EDEM and ANSYS software,the simulation analysis of the corn-soybean general precision seed metering device was carried out.First,the coupling process of the two software was designed,and the seed models of corn and soybean were established by using API particle replacement method,and the flow field inside the seed metering device was simulated and analyzed to analyze the flow field changes under different air pressure,pore diameter and rotational speed.Virtual seeding test was carried out.When the rotation speed was low,the seeding effect was the best with a hole diameter of 5.5 mm,and the pressure required was higher,but the seeding leakage was serious in the high-speed section.When the pore diameter is 6.5mm,the effect is best at the speed of 32 r/min,but when the speed is lower than 24r/min,the replay is serious.(4)Based on Jilin agricultural university engineering training center of the JPS-12 metering,test-bed of corn,soybean general precision metering device has carried on the bench test,and operation test bench for the conveyor belt speed,speed,pressure calibration.Through the experiments of rotating speed and air pressure of seeding disk with different stomatal diameters,the seeding effects of the four stomatal diameters were compared.It can be concluded that the leakage of seeding of 5 mm stomatal diameter is relatively serious,and seed filling can be stable only under higher pressure.When the pore diameter is 5.5 mm,the conformity index is the highest when the speed is in the low speed section,and the leakage index is the highest when the speed is in the high speed section.When the pore diameter is 6 mm and 6.5 mm,the pressure required for normal operation is lower,and the leakage index is lower at high speed,but when the speed is lower than 24 r/min,there is a higher replay problem. |
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