Design And Experiment Study Of Side Throwing Centrifugal Fertilizer Spreader For Lotus Root Field

Among the aquatic vegetables planted in China,Lotus root has the most extensive cultivation area.It has the characteristics of being fond of and tolerant to fertilizer.Lotus root field not only needs a lot of fertilizer,but also need frequent topdressing,Throughout the growing season,it needs 2～3 times of topdressing.However,due to the special growth environment and growth state of lotus root in the field,the mechanization management level of lotus root field is low.At present,the fertilization operation is still dominated by artificial fertilization,Not only high labor intensity,low efficiency,poor effect,but also low fertilizer utilization.Aiming at these problems,a side throwing centrifugal fertilizer spreader was designed to work on the ridge of lotus root field,the bench test was completed,and the contents of the study are summarized as below:(1)Determination of characteristics of typical fertilizer application in lotus root field.The material properties of three kinds of fertilizers commonly used in lotus root field:large granule urea,granular superphosphate and 15-15-15 compound fertilizer were tested.The bulk density and actual density,particle size and its uniformity,compressive strength,and the coefficient of restitution and friction between it and the material used in the fertilizer spreader was measured separately.(2)The mechanical characteristics and impact simulation test of lotus leaf with different maturity.Tensile and puncture tests were carried out on lotus leaf with different maturity and position.Static and dynamic simulation by Ansys software.The stress distribution of lotus leaf surface under the impact of fertilizer was analyzed to predict its failure mode;the variation of the maximum stress at the impact point with the impact speed of fertilizer particles was studied,it provides a reference for selecting the operating parameters of the fertilizer spreader.(3)Overall structure design of lotus root field side throwing centrifugal fertilizer spreader.A side throwing centrifugal distributor was designed according to the actual fertilization requirements,and the structure and parameters of the key components of the side throwing fertilizer spreader,the guide cover and the screw fertilizer discharger are determined.According to the force of single fertilizer particle on the blade,the key factors affecting its movement were determined.The control system of fertilizer spreader is designed for the remote adjustment of operation width and fertilizer amount per unit time of fertilizer spreader.(4)Simulation study on performance of fertilizer spreader.The EDEM single factor simulation experiment of the fertilizer spreader was carried out with the blade inclination angle,blade deflection angle,rotating speed of fertilizer plate and feeding amount as the influence factor.According to the test results,the distribution of fertilizer particles in the operation direction is first increased and then decreased,and there is a fertilizer distribution peak.The significant relationships among the above factors and their interaction terms,coefficient of variation of uniformity and peak distance were obtained by orthogonal rotation simulation experiment.According to the distribution characteristics of fertilizer in the statistical area,the way of installing combined blades in a single fertilizer plate is adopted to make the fertilizer scattered by each group of blades stagger the peak distribution area in the operation area;the simulation comparison test shows that the fertilizer spreading effect is better than that of the fertilizer spreader with single blade structure.(5)Bench test of fertilizer spreader and whole machine of fertilizer distributor.Taking the optimized fertilizer spreading mechanism as the object,the simulation optimization verification test was carried out under the conditions of 1250r/min rotation speed and 6000 pieces/s feed rate.The results show that: the coefficient of variation of uniformity,peak distance and operation width are 23.95%,18.6m and 23.3m respectively;secondly,the influence of feed rate and rotation rate of fertilizer spreader on the test indexes is investigated,The results are the same as the simulation conclusion.The performance test display that: the maximum effective working width of large granule urea,granular superphosphate and compound fertilizer were 24.5m,18.5m and 17.3m respectively,and the minimum coefficient of variation of uniformity were 21.03%,21.69% and 21.60% respectively.