Study On Cavity Structure Optimization Of Vertical Pre - Mill Based On EDEM Simulation

Vertical Pre-mill is a new type of grinding equipment based on the theory of more crushing less grinding,which add a pre-grinding process in the traditional broken grinding process with the purpose of obtaining appropriate particle size range to the mill.As the Vertical Pre-mill have the advantage of high efficiency,low unit energy consumption and appropriate particle size,it has recently received growing interest within the grinding community,and become a hot area in the field of grinding.Only complexity of the Vertical Pre-mill is quite different from that of traditional mill,there are richen theoretic connotation and more wide application foreground.The goal of the thesis is to optimize the structure parameters of the Vertical Pre-mill,in order to improve the grinding efficiency.This thesis is finished by means of in the combination with theoretical analysis, discrete element simulation and experiment.The main works are done as follows:(1) On the basis of experimental data analysis,combined with the theory of accumulative damage,a regression equation of the broken rate with the technology of regression analysis is obtained use MATLAB. According the discuss of the main factors which influencing the ability of crushing energy of the Vertical Pre-mill,they are shown as below:effective collisions and collision speed between the grinding medium and material grain.(2) With the theory of composite motion of a particle,the motion and force of the grinding medium on the ejecting disks are accurate analysed,and the optimum installation angle of the blade is obtained.At the same time,the discrete element simulation also shows that the validity of the theoretical analysis,then the acceleration of the blade is analysed by EDEM simulation,and the optimal number of is obtained.(3) On the basis of the campaign analysis of grinding dielectric through the cylinder stage,cavity model is optimized,namely mounting a guide plate in the cylinder body wall,and the the relationship between the impact velocity and the tangential velocity of the grinding medium and feed plate installation angle are obtained through the analyzed in theory.After that,the analysis of EDEM simulation also shows that the feed plate angle is larger the smaller the particle breakage can be.(4) EDEM particle breakage model is established,and the single particles broken tendency in the feed plate is simulated under different angles,it is shown that the greater the guide plate angle the more time when the particle is completely broken need,and install4block guide plate is the best configuration.(5) The main factors of coordination and the optimal parameters is obtained with the technology of the computer simulation and orthogonal experiment methods,which is the main factors influenced crushing capacity of the Vertical Pre-mill.And the optimal parameters is validated by the simulation of EDEM particle breakage.It is shown from above,these works will provide some available approaches with research on the Vertical Pre-grinding theory and its applications,and there are better theoretical meanings and practical application value.