Energy Consumption Analysis Of Vertical Mill Based On Multi-Scale Bonded Particle Model

Aiming at solve the problem of the high cost and low efficiency phenomenon resulting from too large feeding size,a new type of pre grinding equipment is developed,which is vertical pre mill.Through the impact,extrusion,grinding,cutting and other means to achieve the ore crushing,but its complex pre grinding mechanism to predict the energy consumption has become the focus and difficulty of research.Based on the three broken theory,crushing energy consumption models established only through the simple and rough fitting calculation of the energy consumption of the grinding experiment.However,the effect of ore appearance,mechanical properties and loads on crushing energy consumption isn't took fully account,resulting of the difficulty to quantitatively analyze the relationship between the aforementioned factors and the crushing energy consumption of the pre mill and provide the optimization parameters for the energy conservation of the pre mill.In this thesis,with methods of theoretic analysis,conputer simulation and experimental,the mainly works finished are as follows:A multi-scale particle swarm fragmentation model is constructed with single particle crushing experiment,3D scanning technology and discrete element method.Based on this model and the response surface method,pre mill crushing energy consumption prediction model is established.The main results are as follows:(1)Four typical shape of irregular ore appearance including glob,taper,pillar and plate lamellar,and the contour of the point cloud data obtains by 3D scanning technology,and a 3D reverse modeling of ore in the shape is established by Geomagic Studio software;the shape of irregular ore were quantitative evaluation through three-dimensional model of processing to obtain the geometry parameters of the 2D view and flatness,circularity,practical sphericity and spherical as indicators.Then the evaluation index of reliability is verified with statistical description and the most sensitive evaluation factor for the appearance of the particle is determined.(2)Using the improved WDW-500 testing machine,the four typical irregular ore crushing experiment was carried out.The influence of different extrusion speed and the shape of ore on the corresponding stress and strain was analyzed and statistics of the size of the broken was carried out.The results show that: the ore of the peak stress is bigger and the peak strain is smaller as the loading velocity increases.The greater the degree of sphericity of the ore,the ore peak stress is smaller,larger the peak strain and the crushing granularity can better obey normal distribution.(3)Based on the irregular ore NURBS curve and surface modeling basing on 3D scanning,combined with single particle crushing ore mechanical properties of experimental and crushing particle size distribution function,ore crushing model is established with discrete element method and BPM bond model.And construct the shape geometry,multi granularity distribution,multi mechanical properties of multiscale particle group crushing model by using EDEM API,for in-depth study of all kinds of ore crushing provides new ideas.(4)The structure and working principle of the pre mill are analyzed,and the prediction of the crushing energy consumption is predicted based on the multi scale particle model.To effective power for energy consumption evaluation index,to the rotary speed,filling rate,material ball ratio and ore group sphericity for regression parameters established crushing energy consumption of multiple regression prediction model.In summary,by the typical irregular sample 3D scan,combining with single particle crushing experiments,with discrete element construct multiscale the particle model has strong practicability for analysis of pre mill crushing energy consumption and provides a feasible way for crushing equipment.