Research On Particle Flow Behavior And Structural Optimization In A Hopper Based On EDEM

During the unloading process of the silo,due to the complex flow characteristics of loose materials,problems such as material bonding,silo blockage,and material wear often occur in actual production.Therefore,targeted research on the flow characteristics of particle discharge in the silo can help improve the stability and safety of discharge production or ensure particle quality.In the study of the flow characteristics of particle discharge,the two main flow types of particle discharge flow,namely overall flow and funnel flow,have been widely discussed.When flowing as a whole,the granular material flows uniformly and has a stable unloading process;During funnel flow,the instability of the discharge flow affects the characteristics of the discharged particles and can easily cause fluctuations inside the hopper.During the unloading process,there is a flow pattern transition towards the funnel flow,which is influenced by the structural parameters of the silo and the material characteristics parameters.Therefore,clarifying the influencing factors of flow patterns during the unloading process helps to optimize the structural design of the silo and control the unloading performance in a targeted manner.This article uses the Discrete Element Method(DEM)to simulate the particle discharge flow in the silo and optimize the hopper structure based on the experimental data of the laboratory built silo discharge.Firstly,the EDEM software was studied to calculate the influence of the model parameter settings,half cone angle of the silo,particle radius,and particle moisture content on the silo feeding process.Fifteen sets of research models were established to analyze the flow phenomena caused by different parameter effects.Study the influence of the half cone angle and particle diameter of the silo on the cutting process.The half cone angle of the silo increases,and the flow pattern inside the silo gradually transitions from mass flow to funnel flow.The height of the velocity transition surface inside the silo hardly changes with the semi cone angle of the silo.The influence of the half cone angle of the hopper on the particle flow behavior is directly proportional to the particle diameter.The larger the particle diameter,the more obvious the central flow phenomenon.Based on the simulation results,a triangular cone modified fluid is designed based on the basic parameters of the hopper structure and particle rest angle.Without changing other boundary conditions,a simulation model is established to compare with the original model.The designed fluid modification can directly change the central flow,and the particle flow direction converges towards both sides.The embedding of the modified fluid increases the discharge time and the discharge rate becomes balanced.The fluid modification reduces the stress generated by particles on the hopper wall.Choose PTFE as the coating to improve the contact friction between particles and the inner wall of the hopper.Control the processing method,temperature,and time before spraying to ensure the comprehensive performance of the coating.Use comparative experiments to verify the possibility of its application to the hopper.In addition,four sets of comparative experiments were established to analyze the improvement effect of PTFE coating when used in the hopper.