Parameter Optimization And Experimental Research Of Cone-disc Fertilizer Spreading Device

In order to improve the working stability of the centrifugal fertilizer spreader and the uniformity of fertilizer spraying,this paper analyzes the research progress of fertilizer spreaders at home and abroad,combined with the needs of wheat basal fertilizer spreading and the working principle of existing fertilizer spreaders.Design a double-cone disc centrifugal fertilizer spreading device.First,determine the physical and mechanical parameters of the fertilizer particles and establish the motion model of the fertilizer particles during the spreading process,and establish the fertilizer particle model and geometric model in the discrete element simulation software,simulate the fertilizer spreading process,and determine the best work according to the simulation results Parameter combination,and finally a bench test is performed to verify the simulation results.The main research contents are as follows;(1)To ensure the accuracy of the simulation results,the need to establish a accurate model of fertilizer to wheat basal commonly used chemical fertilizer,urea and diammonium phosphate as the research object,respectively to the physical characteristic parameters: three axis size,moisture content,density,mechanical properties parameters,shear modulus,the coefficient of friction,Angle of repose,crash recovery coefficient were determined.The results were as follows: the equivalent diameters of diammonium phosphate and urea were 3.02 mm and 2.86 mm,and the sphericity was 93.6 and 94.3%,respectively.The true densities were 1.319 g/cm3 and1.339 g/cm3,respectively.The water content was 2.3% and 1.2% respectively.The kinetic friction coefficient is 0.39,0.46,and the static friction coefficient is 0.56,0.52,respectively.The collision recovery coefficients were 0.340 and 0.262,respectively.The shear modulus of diammonium phosphate and urea is 8.3MPa and9.5MPa,respectively.The angles of repose were 34.7° and 33.6°,respectively.(2)The overall structure of the cone-disc fertilizer spreading device is designed,which mainly includes a frame,a fertilizer discharging device,a cone-shaped fertilizer spreading disc,a blade,and a motor.Analyze the process of spreading fertilizer,analyze the force of fertilizer particles in the process of spreading fertilizer,establish the movement model of fertilizer particles on and off the cone-shaped spreading disc and enter the air,and the analytical model shows that the influence of fertilizer The factors of particle movement trajectory are the cone angle of the spreading disc,the inclination angle of the blades,the speed of the spreading disc,the position of the fertilizer opening,and the height of the spreading disc from the ground.Based on existing research and theoretical calculations,design the key components of the fertilizer disc,blades,and fertilizer discharging device,and select the motor.(3)According to the characteristic parameters of the fertilizer particles,the fertilizer model and the geometric model of the fertilizer spreading device are established,the contact model,the time step and the relevant simulation parameters are selected,and the simulation test is designed to analyze the stability and the fertilizer discharge capacity of the fertilizer discharging device at different speeds.Analyzing the influence of single factors such as the speed of the spreading disc,the angle of the blade,and the position of the fertilizer outlet on the distribution of fertilizers,the results show that: when the speed of the outer groove wheel is 75r/min,the fertilizer discharge is the most stable,when the speed of the spreading disc is 75r/min.When 1000r/min,the blade inclination angle is 20°,and the fertilizer opening position is 30 mm,the uniformity of fertilizer distribution is the best,and the coefficient of variation of the lateral distribution is the smallest.Use the post-processing function of EDEM to hide other particles,randomly select a certain particle,visualize the motion trajectory of the fertilizer particle,analyze the force,displacement change,and speed change according to the simulation data,and analyze the motion law of the fertilizer particle.(4)Trial production of the prototype,using the speed of the spreading disc,the position of the fertilizer drop,and the inclination of the blades as the test factors,and the spreading coefficient of variation as the test index.Design a three-factor three-level quadratic regression orthogonal combination test to explore the interaction between the factors on the spreading the influence of the coefficient of variation.According to the test results,a regression model of the speed of the spreading disc,the position of the fertilizer opening and the blade inclination angle on the spreading coefficient of variation was established.The objective function was optimized within the boundary range of each test factor.The optimization result is: The speed of the spreading disc is 1099.08r/min,the blade inclination angle is 4.27°,the position of the fertilizer drop is 29.14 mm,the fertilizer distribution is the best,and the coefficient of variation is 9%.The bench test is carried out.The speeds of the spreading disc are 1094r/min and 1099r/ min,1104r/min,in order to facilitate adjustment,the blade inclination angle is 4.3°,and the position of the drop opening is 29 mm as the test factors.The coefficients of variation at the three different speeds are 10.25%,9.98%,and 10.33%,which are in line with the fertilizer spreader.The coefficient of variation is less than or equal to 20%,and the average errors of the measured value and the optimized value are 12.20%,10.89%,and 14.78% respectively.The results show that the error of the measured value is relatively small,which is basically consistent with the optimized value,which proves that the device satisfies the centrifugal fertilizer application.The operating requirements of the machine.