Simulation And Test Of Spiral Fertilizer Sprinkler Of Mango Fertilizer Based On Discrete Element

In order to solve the problems of man-made fertilization in mango orchard,such as large labor intensity,poor uniformity of fertilization and low fertilizer utilization rate,based on the analysis of the structure and working principle of the existing fertilizer,this paper designs a small spiral-type quantitative fertilizer,which can be used in mango orchard.After measuring the physical and mechanical parameters of fertilizer particles and analyzing their motion,the working process and performance of the fertilizer exhauster were analyzed by means of discrete element simulation software EDEM,combined with theory and experiment.The main contents and conclusions of this study are as follows:(1)Measuring the physical and mechanical properties of fertilizer particles.In order to establish an accurate and real model of fertilizer particles,treating urea particles,compound fertilizer particles and organic fertilizer particles used in mango orchard as the object of study,measuring their parameters respectively,such as the triaxial size,density,moisture content,rest angle and static-static friction coefficient and so on.(2)The structure design and theoretical analysis of the compost are carried out.On the basis of the analysis of the structure and working principle of the existing compost,a small spiral-type quantifier is designed,and the mechanical model of the fertilizer particles in the process of fertilizer removal is established.The kinematics analysis and mechanical analysis of fertilizer particles were carried out.According to the factors such as the amount of fertilizer applied in mango orchard and the growth environment,the structure parameters and working parameters of the fertilizer exhauster were calculated by formula.Finally,the type of motor was selected.(3)Simulation and analysis of the working process of the miniature spiral-type quantitative fertilizer dejector.According to the physical and mechanical parameters of fertilizer particles,the models of fertilizer particles and compost were established,and the contact model was determined and the relevant parameters were set up.The discrete element simulation software EDEM was used to simulate the working process of the fertilizer to observe the trajectory of the single fertilizer particle and analyze its velocity and force change so as to know the movement rule of the fertilizer particle.At the sametime,the influence of different axial rotation speed,different screw blade diameter and pitch on fertilizer discharge was investigated by quadratic regression orthogonal rotation combination design,and the mathematical regression model was established.This model can be used as quantitative fertilization.Provide a theoretical basis.(4)The bench test and parameter optimization were carried out.Firstly,the bench device was built to verify the amount of fertilizer,and the same test scheme as the simulation test was adopted,and the relationship between each factor and the amount of fertilizer discharge was obtained.The relative error between the simulated value and the experimental value is compared.The analysis of the experimental data shows that the maximum relative error is 21.36%,the minimum relative error is 0.65%,and the average relative error is 8.51%,the relative average error of the experiment and simulation is small,which proves the correctness of the discrete element simulation results and the feasibility and effectiveness of using the discrete element method to analyze the screw-type fertilizer exhauster.The effects of different screw blades diameter,pitch and axial rotation speed on the stability of fertilizer removal were investigated.The coefficient of variation of fertilizer release stability was taken as the test index and the results were analyzed according to the test data.The mathematical regression model of the coefficient of variation of fertilizer removal stability was established.Within the constraint range of each factor,the mathematical model was optimized to determine the optimum parameter combination: the diameter of spiral blade was 91.59 mm,the pitch of screw was 55.65 mm,and the rotation speed of fertilizing shaft was 39.45r/min.At the same time,the coefficient of variation of fertilizer release stability reached the minimum value of 12.68%,and the optimized manure removal stability of the compost was compared with that of the optimized one.The uniformity has been improved significantly;In order to verify the correctness of the optimization results and facilitate the processing,according to the optimized optimal parameters combination,the working parameters of the fertilizer-exhauster,namely,the screw blade diameter 92 mm,the pitch 56 mm,and the axial speed 39r/min,were selected to carry out the verification test and repeat the test 10 times.The average value is selected as the final measurement result.The average coefficient of variation of fertilizer removal stability is 12.25%,and the average relative error between the coefficient of variation and the optimization value is 5.88%.The visible error is relatively small.The results ofverification test show that the optimization results are reliable.Therefore,the stability and uniformity of the small screw-type quantitative fertilizer exhauster designed in this paper are good and can be used for quantitative fertilization in mango orchard.