| Aiming at the production status of uneven surface,small plot area and lack of light and simple integrated rape seeder in hilly and mountainous areas,this paper developed a rape seed-fertilizer simultaneous sowing and application integrated device,which can be directly connected to the micro-cultivator to complete precision sowing and fertilization.According to the physical characteristics of rapeseed and fertilizer,the agronomic requirements of rapeseed planting and fertilization,the overall structure and working principle of rapeseed seed-fertilizer simultaneous sowing and application collector were determined.The seed-fertilizer device and air delivery device were designed,and the key structural parameters such as seeding wheel,fertilizer wheel and air delivery device were determined.The EDEM simulation test was used to determine the number of holes in the seeding wheel and the fertilizer wheel.The effects of filling height and rotation speed on the filling and fertilizer filling performance were explored.The disturbance effect of the ring groove on the population during the filling process was verified.The simulation test of seeding and fertilizer performance under vibration and tilt conditions was carried out.The CFD-DEM gas-solid coupling simulation was used to analyze the influence of airflow on the seeding process under different surface slopes.The bench performance test was carried out to determine the optimal working parameters of the collector,and the field verification test was carried out.The main conclusions are as follows :(1)Based on the systematic analysis of the existing precision sowing and fertilization technology of rapeseed,combined with the physical characteristics and agronomic requirements of rapeseed seeds and fertilizers,in order to achieve the goal of simultaneous sowing and fertilization of seed and fertilizer and light and simple integration,the scheme of seed filling,fertilization,airflow seeding and gravity fertilization of rapeseed seed-fertilizer simultaneous sowing and fertilization collector was determined.The overall structure and main components design of rapeseed seedfertilizer simultaneous sowing and fertilization collector were carried out,and the structural parameters of integrated seed-fertilizer box,collector shell,seeding and fertilization mouth were determined.(2)To determine the structural design and parameters of the key components of the rape seed-fertilizer co-sowing and application collector.From the point of improving the capsule capacity of the seed rowing wheel,achieving quantitative seed capsule and improving the stability of fertilizer rowing,and combining the physical characteristics of rape seed and fertilizer with the technical requirements of precision sowing and strip fertilization,a "spoon" type hole is proposed;the key structural parameters and the corresponding structural dimensions of the seed discharge wheel and fertilizer discharge wheel drum were also determined.The innovative proposal is to install the seed wheel and fertilizer wheel on the same shaft to complete the sowing and application of seed and fertilizer together,and to integrate them in a light and simple way;the analysis determines that the dimensions of the seed wheel holes are 3.7mm,3mm and 2.2mm in length,width and height respectively,the number of holes in a single row is 18,the diameter of the seed roller is 80 mm and the axial length is 30mm;the dimensions of the fertilizer wheel holes are 15 mm in length,20 mm in width and14.3mm in height respectively,the number of holes in a single row is 15,the diameter of the seed roller is 80 mm and the axial length is 40 mm,The size of fertilizer wheel holes are 15 mm,20mm,14.3mm in length,width and height respectively,the number of single row holes is 15,the diameter of seeding roller is 80 mm and the axial length is40 mm.(3)Simulation experiments on the performance of a seed-fertilizer collector based on EDEM simulation for rape.Specifically,it includes:(1)The test determined that the number of holes in the seeding wheel and the fertilizer wheel was 18 and 15 respectively,which could meet the requirements of sowing and fertilization at the same speed.The effects of the filling height of the collector on the seed filling and fertilizer filling performance were analyzed.The test showed that the filling height was too low,which would lead to the seed and fertilizer could not be filled with the hole and could not meet the displacement requirements.When the filling height was too high,the dragging phenomenon occurred and the displacement increased.When the filling height was 15 mm ～ 25 mm and the filling height was 25 mm ～ 35 mm,the seed filling and fertilizer filling performance was better.The two-factor test of filling height and rotational speed was carried out.When the rotational speed of the collector was 10 r / min ～ 40 r / min,the corresponding seed layer height range was 22.5mm ～ 25 mm,and the fertilizer layer height range was32.5mm ～ 35 mm,the filling and fertilization performance was better.(2)It is verified that the type hole wheel with ring groove can effectively improve the active state of the population,and the kinetic energy of the population in the seed filling room is 103 % higher than that of the type hole wheel without ring groove.With the increase of rotational speed,the average kinetic energy of the population increases gradually,and the fluctuation range of kinetic energy decreases gradually,which is conducive to stable seed filling.When the rotation speed was 20 r / min,30 r / min and40 r / min,the average kinetic energy of the population increased by 154 %,317 % and446 % respectively compared with that at 10 r / min.(3)The seeding and fertilizer performance of the collector under vibration was analyzed.When the amplitude range was 0 ～ 1mm and the frequency range was 0 ～5Hz,the seeding amount remained relatively stable,the seeding was less affected by vibration,the type hole could be stably filled,and the mobility of the population was enhanced to a certain extent.When the amplitude is greater than 1mm and the frequency is greater than 5Hz,the seeding amount is greatly affected by the vibration,the seeding amount and the fertilizer amount are significantly reduced,and the hole cannot complete the filling.When the amplitude is 0 ～ 4 mm and the frequency is 0 ～ 20 Hz,the amount of fertilizer is relatively stable,which can enhance the fluidity of the fertilizer group,effectively avoid the fertilizer arching and improve the fertilizer filling performance of the hole.When the amplitude is greater than 4mm and the frequency is greater than 20 Hz,the amount of fertilizer is greatly affected by vibration,and the performance of fertilizer is reduced.(4)The seeding and fertilizer performance of the collector in the inclined state was analyzed.When the backward angle of the collector was-25 ° ～-6 °,the total seeding rate decreased by 9.8 % and the total fertilizer rate decreased by 17.3 %.When the rake angle of the collector is 6 ° ～ 15 °,the influence on the amount of seeding and fertilizer is relatively gentle.When the current inclination angle ranges from 15 ° to25 °,the total amount of seeding increases by 64.6 % and the total amount of fertilizer increases by 10.3 %.Therefore,when the collector meets continuous uphill or downhill when working in hilly and mountainous areas,it can be selected along the uphill direction as the forward direction of the machine to reduce the influence of slope change on the collector.When the lateral inclination angle of the collector increases,the amount of seeding and fertilizer in each row increases gradually with the increase of the inclination angle.When the lateral inclination angle is 6 ° ～ 25 °,the maximum rate of change of the amount of fertilizer is 33.6 %,and the maximum rate of change of the amount of seeding is 20.9 %,but the coefficient of variation of the consistency of the seeding and fertilizer is less than 5 %.Therefore,when the inclination angle increases,the rotation speed can be reduced to adapt to the change of seeding rate and fertilizer rate,thereby reducing the impact of lateral inclination of the surface.(5)Analysis of seed discharge and fertilizer discharge performance of the collector in the tilted condition.The effect on the total fertilizer discharge volume is more obvious when the collector is tilted backward,and the effect on the seed and fertilizer discharge volumes is more moderate when it is tilted forward.The total seed discharge volume increased by 64.6% and the total fertilizer discharge volume increased by 10.3%when the front tilt angle reached 15° compared with the no tilt state due to the seed discharge wheel dragging phenomenon When the collector is tilted backward,the effect on seed discharge is less than that on fertilizer discharge,and when the collector is tilted forward,the effect on seed discharge is greater than that on fertilizer discharge.(4)Based on CFD-DEM gas-solid coupling simulation,the influence of different slope air-assisted on seed movement was analyzed.According to Fluent simulation analysis,when the inlet angle is 20 °,the airflow distribution at the outlet of the pipeline is relatively stable,and the center of the pipeline is in the acceleration stage,which is conducive to the smooth acceleration of seeds in the pipeline.According to the CFD-DEM gas-solid coupling simulation test,the stress and velocity state of the seed in the pipeline are analyzed.It is concluded that the air flow can effectively accelerate the seed transportation.When the local surface slope changes or the installation position of the collector is low,the air flow can effectively avoid the seed retention in the pipeline.(5)The bench performance test and field test of rapeseed seed-fertilizer cosowing and co-application collector were carried out.The quadratic regression equation of rotational speed and seed and fertilizer supply rate was established,and the regression fitting equation was verified.The absolute error between the actual value and the theoretical prediction value was less than 5 %.When the rotation speed of the collector is 10 r / min ～ 40 r / min,the variation coefficient of the stability of the seeding amount and the fertilizer amount is less than 5 %,which meets the quality requirements of the seeding machinery operation.The results showed that the planting density of rapeseed was 65 plants / m2,and the relative error between the actual application amount of fertilizer and the predicted model value was 3.25 %,which met the agronomic requirements of rapeseed planting. |
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