| Anhui Province is one of the main provinces to promote the compound planting of corn and soybean,but it lacks the special compound precision planting technology of jade bean and auxiliary equipment.In view of the problems that the existing pneumatic disc seed drainer is not easy to achieve the simultaneous use of corn and soybean seed drainer and that the high speed seed drainer has broken strips due to the pattern hole leakage and filling,based on the perturbation adsorption principle,a precise seed drainer of jade bean was designed,which combines the dynamics and kinematics theory,DEM numerical simulation,high speed camera technology and performance test.The optimization of seed tray structure and adsorption performance of seed platter were studied,which improved the performance of corn and soybean seed platter under high speed operation.The study provided a reference for the development of high speed and precision equipment for corn and soybean seed platter.The main research conclusions are as follows:(1)The maize and soybean varieties commonly used in Anhui Province were selected,and the basic physical parameters and tribological property parameters of maize and soybean seeds were determined.The parameter determination provided a reference for the parameter design of the key components of seed disperser,and provided a basis for the establishment of discrete element seed particle model and simulation parameter calibration.(2)Based on the physical and mechanical characteristics of seeds,combined with the agronomic requirements of strip composite planting and the principle of disturbance adhesion suction,we designed the precise seed arrangement device of jade bean with cavity and disk combined orifice structure,described the working principle and main technical parameters of the device,and established the mechanical model of filling and carrying seed process by using the kinematic and dynamic theories.The key structural parameters of the seed separator were analyzed and determined,and the key factors affecting the adsorption performance were determined.(3)The discrete element method(DEM)was used to model corn and soybean seed particles,and the location and radius of the subball of the multi-ball model of seed particles with different shapes were given.The influence of four different types of seed trays on the disturbance performance of the population in the seed chamber was explored.The tangential velocity and drag seed filling Angle of the population close to the side of the seed trays were extracted.There was a positive correlation between the average tangential velocity and the drag filling Angle of the same type of disk.The tangential velocity and drag filling Angle of the disturbed population of parabolic disk were greater than those of the other three types of disk.(4)The optimization test of seed disk type of seed platter was carried out.The unit forward speed and seed disk type were taken as test factors,and the leakage rate and drag filling Angle were taken as evaluation indexes.The test showed that: the larger the drag filling Angle caused by different types of seed disk to population disturbance,the lower the leakage rate of bench test.Parabolic disk < involute disk < straight tooth disk < plane disk,the relationship of drag seed filling Angle is as follows: parabolic disk > involute disk >straight tooth disk > plane disk,indicating that the seed filling performance of the four types of seed plates is better.When the working negative pressure of the parabolic seed plate is 3.0k Pa and the forward speed is 4-7km/h,the leakage rate of corn and soybean seeds is not more than 3.6%.(5)The adsorption performance test was carried out to investigate the influence of working negative pressure and forward speed on the filling performance of parabolic seed tray.The results showed that: under the working negative pressure of 2.0～4.0k Pa and the forward speed of 4～7km/h,when the negative pressure reached above 3.0k Pa,the qualified rate of corn and soybean seed filling could reach more than 96%.The regression equations of hole rate and hole particle number pass rate were obtained and multi-objective optimization was carried out.The results are as follows: When the forward speed of corn and soybean units is 5km/h and the working negative pressure is 3.47 k Pa and 3.67 k Pa,the hole percentage of corn and soybean units is 0.24% and 0.14%,and the qualified percentage of hole number is 98.9% and 98.6%,respectively.The field experiment showed that the parabolic seed tray still had good filling performance under the real vibration environment,meeting the related requirements of sowing.By comparing the parabolic seed tray and the undisturbed seed tray,it was found that: At the forward speed of 4km/h,the difference in the leakage rate of corn and soybean is only 5.2% and 4.1%,respectively.When the forward speed is 7km/h,the difference in the leakage rate of corn and soybean is15.3% and 13.6%,respectively. |
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