Optimization design of fertilizer apparatus owned arc gears based on discrete element method

To improve the uniformity of the flow when fertilizer apparatus discharges fertilizer,a kind of fertilizer apparatus owned arc gears was designed.Also,the design and working principle of its general structure and key components were analyzed theoretically.Aiming at exploring the influence of arc structural parameters to the performance of arc gears discharging fertilizer,DEM simulation was used in this study.Fertilizer apparatus owned arc gears was taken as the research object to analyze the influence of two key components including the arc radius of gears’concave-grooves and the minimal length between two mutual meshing gears.The variation coefficient of fertilizer discharging amount stability and the linear determined coefficient of fertilizer discharging amount in unit time as evaluation index were selected.Two factors and five levels quadratic rotation orthogonal experiment was applied,and Design-Expert 8.0 software was used to achieve data processing and analysis.The results of experiment indicated that the arc radius of gears’concave-grooves had significant effect on the linear determined coefficient of fertilizer discharging amount in unit time,and the minimal length between two mutual meshing gears had significant effect on the variation coefficient of fertilizer discharging amount stability.The optimum structural parameters were 8.54 mm as the arc radius of gears’concave-grooves and 5.22 mm as the minimal length between two mutual meshing gears.Upon this circumstance,the variation coefficient was 0.28 and determination coefficient was 0.9972.The optimum apparatus was selected to conduct the bench test and field simulation test.The results indicated that the variation coefficient is 0.27,and the linear determined coefficient of is 0.9980.The results of simulation experiment were anastomotic basically with the real result,which showed that DEM simulation technology was usable to the experiment of testing fertilizer discharging.The results of this research can provide a reference to the improving of performance in discharging fertilizer.

Design and experiment of vertical pneumatic fertilization system with spiral Geneva mechanism

In the traditional fertilization method,a large amount of fertilizer is applied,which causes congestion easily.It is not conducive to the sustainable development of agriculture.In this work,a vertical pneumatic fertilization system with a spiral Geneva mechanism was designed according to the operational requirements of variable-rate and smooth fertilization.The uniformity in discharging fertilizer with different spiral angles was simulated and analyzed by extended discrete element method(EDEM)based simulation software,from where the spiral angle of the fertilizer discharge wheel was determined to be 45°.The fertilization system includes a fertilizer apparatus with a spiral Geneva mechanism,whose optimal performance parameters were obtained from the bench experiment.The accuracy and uniformity of the fertilizer application system were taken as the evaluation indicators.The linear relationships of the discharged amount of fertilizer with the rotational speed and the opening of the fertilizer discharging wheel were verified by both static blowing fertilization and field experiments.The static blowing experimental results show that the discharged amount of fertilizer has a high linear correlation and accuracy with both the opening and rotational speed,and the highest correlation occurs with the rotational speed.The rotational speed and opening have significant effects on the discharged amount of fertilizer and the average coefficient of variation.The effect of the rotational speed was the most significant.According to the model obtained by multiple regression fittings,the optimal parameters were determined when the average coefficient of variation was small,the rotational speed was 15.9 r/min and the opening was 34.4 mm.Therefore,the purpose of precise fertilization can be achieved by adjusting the opening or rotational speed in a way to get the exact amount of fertilizer discharged as required by the corresponding crops.The field experiment showed that the variation coefficient of each fertilizer discharged decreases first and then increases with an increasing opening under different rotational speeds,which is consistent with the theoretical value.When the opening was 40 mm or 50 mm,the variation coefficient reached the minimum value,which is far less than the qualified index of 7.8%.In the static blowing experiment and the dynamic field experiment,the stability of the fertilizer discharging device can be significantly enhanced with the utilization of the pneumatic conveying fertilizer.This study can provide a theoretical reference for parameter selection and optimization of vertical spiral fertilization systems.