Analysis And Optimization Study Of Pendulum Mill Based On CFD-DEM Co-simulation

R-type pendulum mill(referred to as pendulum mill)as the current powder processing industry commonly used in the basic equipment,its application value is high,in addition to meet the basic needs of powder production,pendulum mill at the same time with simple operation,wide application,easy maintenance and other advantages.It is used in many industries such as mining,chemical,food and pharmaceutical.However,because of the structure of the pendulum mill,it is difficult to control the wear of its components,such as grinding rollers,air-return duct,spades and other components are easy to wear,and a series of reasons limit the further development and application of the pendulum mill.As the main component affecting the material particle trajectory in the pendulum mill,the structure and installation parameters of the spade play an extremely important role in optimizing the performance of the pendulum mill.In this paper,the combined CFD-DEM(Computational Fluid Dynamics-Discrete element method)co-simulation method is used to simulate the material particle trajectory,the flow field in the air-return duct and the flow field in the mainframe,and the effect of the main operating parameters and structural parameters on the wear of the air-return duct and the mill yield is studied by means of response surface design.The influence of the main operating parameters and structural parameters on the wear of the air-return duct and the yield was investigated through the response surface design method.The details are as follows:1.First of all,the global status of grinding equipment and the current situation of the use of computer simulation software is discussed in more detail,so as to determine the main research content and technical route of this paper.2.By analyzing the structure of the pendulum mill mainframe and its motion principle,the particle motion model was constructed,and the dynamics of the particles were analyzed,and the factors affecting the grinding efficiency and wear,such as the spindle speed,spade degree,grinding force and engagement angle,were analyzed.According to the operating parameters in production,rigid body dynamics simulation was carried out by Adams simulation software.3.By adjusting the size of the air inlet of the duct,the flow field at the bottom of the pendulum mill was improved to make the flow field at the bottom of the mill more evenly distributed.4.The changes of spindle speed and spade degree were studied by CFD-DEM cosimulation of the pendulum mill mainframe,respectively.The particles were captured by the grinding rollers and grinding rings from the collision energy spectrum and the collision accumulated power energy spectrum were analyzed.The variation pattern of the mill yield and the wear of the air-return duct were analyzed.5.A response surface simulation test was conducted to study the effects of three factors:spindle speed,spade degree and wind velocity on the yield and wear of the air-return duct,and the significance of the three factors and their interactions were analyzed;the optimal combination of response surface: spindle speed of 120 rev/min,spade degree of-12° and wind velocity of 46 m/s can obtain the maximum yield and minimum wear of the air-return duct.6.A layered spade was designed to not only reduce the unevenness of grinding roll wear,but also improve the grinding yield of the mill.And a response surface simulation test was conducted to study the effects of three factors on the yield and roller wear with the spindle speed,spade height and second-platform height as the three factors and the yield and roller wear variance as the optimization objectives.The optimal results were obtained when the spindle speed was 103.17 rev/min,the shovel height was 349.76 mm,and the secondary table height was 93.64 mm.The research work of the thesis,using rigid body dynamics simulation,combined CFDDEM co-simulation and response surface optimization method as the research means,provides the direction and theoretical basis for the optimization of the production efficiency of the mainframe of the pendulum mill and the structural optimization of the spade components.