组合振动筛的参数优化及筛面颗粒运动仿真分析

发布时间：2018-09-12 15:32

【摘要】：组合振动筛是一种新型研制开发的振动筛,解决一台筛机有不同的振幅、振动强度、筛面倾角和堵塞问题,提高了筛分效率。本文研究的组合振动筛,上筛采用高频小振幅,下筛采用低频大振幅。研究其上下筛参数的配合优化设计,并对其筛面上物料的运动规律的揭示,利用EDEM对振动筛颗粒物料的仿真分析,找出规律确定其各参数对振动筛的影响。本文主要内容有:(1)对组合振动筛参数进行正交试验分析,以组合振动筛的单位生产率功耗建立数学模型,定其为目标函数,利用遗传算法对其进行优化设计,得到一组最佳的参数:上筛振幅为4.12mm、倾角为23.56°、振动强度为4.11;下筛振幅8.2mm、下筛倾角19.73°、振动强度5.021。总功耗由0.063kw/t/h降低至0.057kw/t/h,功耗优化了近9%。(2)对组合振动筛颗粒物料仿真研究分析,建立物料颗粒接触模型,用EDEM软件,对组合振动筛筛面上颗粒物料的运动分析。借助颗粒粘结模型,以物料在筛分过程中物料间键粘结的平均数和物料对筛面平均切向力作为衡量松散效果的指标,分析振幅、振动强度和筛面倾角对其影响,随其增加,松散效果增加,其中,振动强度对筛面上物料松散度影响最大,筛面倾角影响最小。分析了单颗粒在组合振动筛面上跳动规律,振幅对筛面上颗粒抛掷后离开筛面的高度影响最大,倾角影响最小。这是因为,在其他条件相同情况时,较小振幅下,物料几乎不被抛起,物料在筛面上发生滚动,随振幅的增加,物料慢慢被抛起在筛面上跳动。增大振幅、振动强度及筛面倾角使物料松散效果和颗粒跳动离开筛面高度的增加,有利于物料快速松散。(3)采用软干球模型和分层理论对组合振动筛筛面上物料颗粒群进行离散元分析。分析得到不同粒度和物料的颗粒群在筛面上的平均分层速率曲线。达到稳态时,上下筛颗粒分层速率幅值分别在0.58m/s和0.45m/s左右,分析振幅、振动强度和倾角与筛面上物料平均速度之间的关系,得到振动参数与平均速度的回归模型。筛面倾角对筛面上颗粒群平均速度影响最大。分析得到筛面上物料具有较大的速度有利于物料快速分层。(4)运用EDEM软件及软干球模型,对组合振动筛进行三维离散元模拟仿真。提出动态累计筛分效率的概念,对筛面长度和筛分效率的研究,得到筛长和筛分效率的回归模型,筛分效率随筛面长度增加而增加,当筛面长度大于900mm,筛长与筛宽比值大于4时,筛分效率不再明显增加。
[Abstract]:The combined vibrating screen is a new developed vibrating screen, which solves the problems of different amplitude, vibration intensity, inclined angle and clogging of a screen machine, and improves the screening efficiency. The combined vibrating screen studied in this paper uses high frequency and small amplitude for upper sieve and low frequency and large amplitude for lower sieve. The optimum design of the upper and lower screen parameters is studied, and the movement law of the material on the screen surface is revealed. The simulation analysis of the particle material of the vibrating screen is carried out by using EDEM, and the influence of each parameter on the vibrating screen is found out. The main contents of this paper are as follows: (1) the parameters of the combined vibrating screen are analyzed by orthogonal test, and the mathematical model is established based on the unit productivity power consumption of the combined vibrating screen, which is defined as the objective function, and the optimization design of the combined vibrating screen is carried out by using genetic algorithm. The optimum parameters were obtained: the amplitude of the upper sieve was 4.12mm, the inclination angle was 23.56 掳, the vibration intensity was 4.11, the amplitude of the lower sieve was 8.2 mm, the angle of the lower sieve was 19.73 掳, and the vibration intensity was 5.021. The total power consumption is reduced from 0.063kw/t/h to 0.057 KW / t / h, and the power consumption is optimized by nearly 9%. (2) the particle contact model of the composite vibrating screen is studied and analyzed by simulation, and the movement analysis of the particle material on the screen surface of the combined vibrating screen is carried out by EDEM software. With the aid of particle bonding model, the average number of bond between materials and the average tangential force of material to sieve surface are taken as indicators to evaluate the loose effect. The effects of amplitude, vibration intensity and sieve inclination angle on it are analyzed. The influence of vibration intensity on the material looseness on the screen surface is the greatest, and the influence on the angle of the sieve surface is the least. The jumping rule of single particle on the surface of the combined vibrating screen is analyzed. The amplitude has the greatest influence on the height of the particles on the screen surface after throwing away from the screen surface, and the influence of inclination angle is the least. This is because when other conditions are the same, when the amplitude is small, the material will not be thrown up, and the material will roll on the screen surface, and with the increase of amplitude, the material will be slowly thrown up on the screen surface. The increase of amplitude, vibration intensity and the angle of inclination of the sieve surface makes the loose effect of the material and the runout of the particle from the height of the sieve surface increased, (3) using soft dry ball model and stratification theory, the particle group on the screen surface of combined vibrating screen is analyzed by discrete element method. The average delamination rate curves of different particle sizes and particle groups on the sieve surface were obtained. When the steady state is reached, the delamination rate amplitude of the upper and lower sieve particles is about 0.58m/s and 0.45m/s, respectively. The relationship between the amplitude, vibration intensity and dip angle and the average velocity of the material on the sieve surface is analyzed, and the regression model between the vibration parameters and the average velocity is obtained. The average velocity of particle group on the sieve surface is most affected by the inclination angle of the screen surface. It is found that the material on the screen surface has a large speed which is conducive to the rapid stratification of the material. (4) using the EDEM software and the soft dry ball model, the three-dimensional discrete element simulation of the combined vibrating screen is carried out. The concept of dynamic cumulative screening efficiency is put forward. The regression model of screen length and screening efficiency is obtained by studying the sieve surface length and screening efficiency. The screening efficiency increases with the increase of sieve surface length. When the sieve surface length is greater than 900mm and the ratio of sieve length to width is greater than 4, the sieving efficiency will not increase significantly.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD452

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