Simulation Study Of Particles Flow On The Vertical Dryer Based On DEM

In the feed production, the initial processing of raw materials to the final manufactured goods will face to a large number of particles need treatment, drying, cooling, conveying and other operation processes. However, as a result of the complexity of granular material physical and mechanical characteristics, people’s view of specific work mechanism of various flow of granular material is far from the guidance of production target. With the development of computer technology, combined with the experimental research and numerical simulation technology, the analysis and research of production process of pellet feed is available from the micro-level.The discrete element method (DEM) is used in granular media research field numerical methods can be used for the analysis of particle law of motion, the interaction between the particles between cells and particles, and mechanical devices. This paper use the discrete element method in the vertical drying equipment in the distribution process of pellet feed motion characteristics and drying unit for gas solid coupled wind field parameters for simulation, based on the task group’s developed-vertical drying equipment.The research work are as follows:(1) Experimental measurement of the physical and mechanical properties of pellets was evaluated, which provides a reference for EDEM simulation. According to the experiment, the average porosity is0.459, the real density is768.3kg.m-3, the static friction between the pellet feed factor is0.408, the dynamic friction factor is0.355, the static friction coefficient between the feed pellets and iron is0.298, the dynamic friction factor is0.235. Feed pellets and iron the restitution coefficient of0.34between the pellet feed restitution coefficient of0.27. The pellets elastic modulus is243.95MPa.(2) Based on the basic principle of the discrete element method (EDEM), the judgment method of contact between the particles and particles, particles with the boundary model and contact was determined, while taking advantage of the Hertz theory of contact mechanics model. Were constructed based on the physical dimensions of the vertical dryer fabric device developed by our team, rotating cloth bodies, physical model of uniform material bodies and unloading bodies. EDEM discrete element software for simulation of particulate material was used in movement behavior and distribution of state agencies, and simulation data analysis and experimental verification. (3) Build the model of vertical dryer unit, the boundary conditions and parameters of the flow field computational domain was set according to the drying unit wind field measured data, using the discrete element method to establish the initial conditions of coupled solid phase (particulate phase), the granular layer fill heights was100mm and160mm respectively, non-steady-state CFD-EDEM Euler coupling model, the matching time step to simulate the height of the material layer airflow in the drying unit field distribution law in the drying chamber of the drying unit simulation. Wind field simulation results and actual test measurement results, in line with the actual law.