基于DEM的强力混合机湿颗粒混匀过程中桨叶磨损分析（英文）

Analysis of blade erosion of intensive mixer based on DEM during wet particles mixing

强力混合机混匀过程中由颗粒流引起的磨损是影响混合机寿命的主要因素,颗粒中混有的少量液体对颗粒流形态以及磨损均有重要的影响。本文基于离散元法(DEM)研究了湿颗粒混匀过程中强力混合机桨叶的磨损,通过Mikami模型模拟湿颗粒中液桥力的复杂作用。采用四种磨损模型进行预模拟,并通过实验得出Huang模型为模拟强力混合机桨叶磨损的最优模型,最后分析了颗粒湿度、粒径以及混合机参数对磨损的影响。试验结果表明:桨叶的磨损主要集中在桨叶的端部和前部;颗粒的湿度能增大颗粒对桨叶表面的作用力及颗粒-桨叶的相对速度而加剧桨叶磨损;桨叶速度的增加和颗粒粒径的减少同样能加剧桨叶的磨损;而料筒转速对桨叶的磨损影响较小。研究结果对于强力混合机结构改进具有一定的意义。

Erosion caused by particle flow during the mixing process is a key factor affecting the intensive mixer life.For wet particles,the existence of liquid has an effect on the particle flow and erosion due to cohesion force of liquid bridge.In this paper,DEM simulations were carried out to investigate the blade erosion of intensive mixer during wet particles mixing process.The Mikami capillary force model was introduced to simulate the complex effects of liquid bridge between wet particles.4 commonly used erosion models were combined to predict the blade erosion and the Huang’s erosion model was finally chosen after comparing with the experimental data.The results showed that the blade erosion was focused in the divisions of 35 to 55 mm from the reference point in radial direction,and in the division of 0 mm from the reference point in the azimuthal direction.The compressive force and particle relative speed of blade were more pronounced due to the cohesion force of liquid matter,leading to the increase of blade erosion.High blade speed and small particle size intensified the blade erosion,whereas vessel speed had little influence on it.The results obtained can be used to improve the design of intensive mixer.