| In view of the large peanut grain,thin skin and irregular shape,not easy to be adsorbed,single mechanical or air suction seed discharge technology has low seed filling rate,high mechanical damage of seeds,high negative pressure energy consumption,unstable seed adsorption and other problems.To enhance the filling seed effect of seed,to reduce the energy consumption of negative pressure,streamline institutions,improve performance,avoid row kind of plate and the negative pressure air chamber,wear pads wear between the row of kind of plate and negative pressure air chamber synchronous rotation,special-shaped take kind of guide rail with,negative pressure filling,and,since the falling and brush the secondary cleaning ways,design of a pneumatic guide rail type peanut precise metering device,It can effectively improve the filling performance of seed metering device,so as to realize the purpose of precise peanut seeding.(1)Using the "Si Lihong" peanut variety as the research object,the characteristics of seed materials were determined,including seed geometric size,moisture content,angle of rest and sliding friction angleetc.to provide theoretical basis for the design of pneumatic guide precise peanut seed metering device.(2)The overall structure and operational principle of the seed metering device were analyzed.The diameter and wall thickness of the seed metering disk and the structure and inclination angle of the specialshaped seed metering guide were designed.When the speeds of the seed metering device were 15～40 r/min,the vertical angle θ’ between the centroid of seeds in the special-shaped seed metering guide and the seed metering disk was 60 °,The angle θ of special-shaped guide is 51.87～62.20 °.FLUENT simulation software were used to simulate and analyze the negative pressure flow field of straight hole,conical hole and sunken hole.when the number of type hole Z was 10,with the flow velocity higher,the better the seed filling effect,the negative pressure type hole was designed as straight hole,The process of seed filling,carrying,cleaning and throwing were analyzed respectively: in the process of seed carrying,the maximum theoretical negative pressure required for adsorbed seeds is 0.3kpa through calculation;In the process of seed seeding: in order to make the seed seeding smoothly,the trapezoidal inclined angle of the special-shaped seed picking guide rail is designed to be 120 °.(3)With pneumatic guide rail type peanut precise metering device as the research object,the peanut seeds discrete element model is established and the row of kind of 3D model,with aliens take kind of guide rail inclination angle(52～62 °),metering device speed(15 ～ 40 r/min)for the test factors,seed index(single grain filling,repeat filling),leakage indices for the test,the results of simulation test were optimized and verified.The results showed that when the speed of seed metering device was 30 r/min and the optimal inclination angle of special-shaped seed guide was 60 °,the seed filling effect was the best,and the seed filling index was 96.8 %.(4)The bench test was carried out to explore the seed metering performance of pneumatic guide precise peanut seed metering device by taking the speed of seed metering device(15 ～ 40 r/min)and negative pressure(0.1 ～ 1.0 kpa)as test factors.Based on the method of quadratic orthogonal rotation combination,the quadratic regression equation between two factors and three indexes is established.Experiments and verification were carried out,and the results showed that the optimal seeding performance was achieved when the rotation speed of the seeding machine was 29.0 r/min and the negative pressure was 0.6 kpa.At this time,the qualified index of seeding performance was 92.5%,the replay index was 4.0 % and the missed seeding index was 3.5 %,which could achieve the requirements of precise seeding of peanut. |
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