Simulation and Parameter Optimization of Centrifugal Fertilizer Spreader for Tea Plants

Abstract:

No customized fertilizer machines are widely applied in tea fields and traditional spreaders for field crops are constrained by the narrow row spacing of tea trees when used for tea fields. According to the row spacing of tea trees and the characteristics of fertilizer, fertilizerpushing blades were deployed away from the center of the centrifugal plate with their adjustable offset angles, and the horseshoeshaped outlet was adopted. A dynamic model of the fertilizer particle’s movement on the centrifugal plate was established through force and kinetic analysis. With orthogonal test design and central composite design in Design-Expert, the fertilizer spreading process was simulated with EDEM based on a discrete element model. A regression equation of the relationship between variation coefficient of fertilizer particles’ distribution and spreader forwarding speed, blade number and blade offset angle was obtained, and the order of the influence of the above factors on the variation coefficient of fertilizer particle distribution was: blade number, forwarding speed, blade offset angle. The influence of the interaction between blade number and offset angle on variation coefficient was significant, while the influence was less for the interaction between forwarding speed and blade offset angle. It is found out after regression analysis and optimization that the variation coefficient decreased to the minimum of 6.12% when blade number was 5, forwarding speed was 0.6 m/s and blade offset angle was 13.44°. The validation experiment showed that the average relative error between the measurements and the predictions was 11.18%. Therefore, the EDEM simulation model could be used to optimize operation parameters of a centrifugalplate fertilizer spreader, and achieve the expected spreading uniformity in tea fields.