基于密实度及细颗粒比的振动筛分松散及分层的研究

发布时间：2018-05-14 17:31

本文选题：振动筛 + 松散　；参考：《华侨大学》2013年硕士论文

【摘要】：振动筛是工程上常用的筛分设备，通过对物料施加振动，从而使得物料松散，分层，触筛与透筛。物料的松散与分层是影响筛分效率的主要因素。以计算机技术、力学理论为依托的筛分过程数值模拟已成为筛分机理研究的重要手段。本文运用DEM（Discrete Element Method，离散单元法）对振动筛筛分过程中的松散和分层进行数值模拟研究。在建立了振动筛三维模型的基础上，基于离散单元法的EDEM软件，进行筛分实验，分析各种筛分参数对松散和分层的影响。详细地研究了筛分过程，主要内容如下： 1．文中详细地分析了筛分过程中的物料松散和分层现象，定义了物料的密实度、分层细颗粒比、松散区域、分层区域等概念，建立了密实度与筛分时间、松散区域下限高度的关系曲线图，从而验证定义的合理性，为进一步研究参数对松散及分层的影响提供理论指导。 2.通过设计单因素实验，系统地分析了筛面结构参数、振动参数对物料密实度、分层细颗粒比的影响，得到了在取得较好的物料松散与分层效果时的结构参数和振动参数的最优值，同时解释了参数影响筛分效率的原因。 3.在单因素实验基础上，设计和实施具有交互作用的正交实验，每一参数各取三个水平，每一大类参数各设计27组实验。通过数值仿真模拟，分析得到物料密实度及细颗粒比的最优参数组合及各参数影响物料松散与分层的显著性，与单因素实验得到的筛分效率对比，结果显示筛分效率有了较好的提高。 4.在获得最优振动及结构组合参数的条件下，研究不同生产工艺参数与物料松散及分层的变化规律，并对参数进行修正。仿真结果与实验结果对比：仿真结果得到的参数对物料松散、分层、筛分效率影响的规律与工业的实验结果是一致的，很好地解释了筛分理论。本文所建立的用于研究筛分过程中物料松散及分层的特征量反映了实际振动筛的特征和规律，是分析和研究筛分机理的有效方法。
[Abstract]:Vibrating screen is a commonly used screening equipment in engineering. By applying vibration to the material, it makes the material loose, stratified, touched and sieve through. Material looseness and delamination are the main factors affecting screening efficiency. Numerical simulation of screening process based on computer technology and mechanical theory has become an important means of screening mechanism research. In this paper, DEM(Discrete Element method is used to simulate the looseness and delamination of vibrating screen. Based on the three-dimensional model of vibrating screen and EDEM software of discrete element method, screening experiments were carried out to analyze the influence of various screening parameters on looseness and delamination. The screening process is studied in detail. The main contents are as follows: 1. In this paper, the phenomena of material looseness and delamination in the screening process are analyzed in detail. The concepts of material density, stratified fine particle ratio, loose area and stratified area are defined, and the compactness and screening time are established. In order to verify the rationality of the definition, it provides theoretical guidance for further study on the influence of parameters on looseness and stratification. 2. By designing single factor experiment, the effects of structural parameters and vibration parameters of sieve surface on material compactness and the ratio of layered fine particles are systematically analyzed. The optimum values of structural parameters and vibration parameters are obtained when the material is loose and stratified, and the reason why the parameters affect the sieving efficiency is explained at the same time. 3. On the basis of single factor experiment, the orthogonal experiment with interaction is designed and implemented. Each parameter takes three levels, and 27 groups of experiments are designed for each large class of parameters. Through numerical simulation, the optimal parameter combination of material density and fine particle ratio and the significance of each parameter affecting material looseness and delamination are obtained, which are compared with the screening efficiency obtained by single factor experiment. The results show that the screening efficiency has been improved. 4. Under the condition of obtaining the optimal vibration and structural combination parameters, the variation law of different production process parameters and the loose and stratified materials are studied, and the parameters are modified. The simulation results are compared with the experimental results. The simulation results show that the influence of the parameters on the material is loose, stratified and sieving efficiency is consistent with the industrial experimental results, and the sieving theory is well explained. The characteristic quantity established in this paper, which is used to study the loose and stratified material in the screening process, reflects the characteristics and laws of the actual vibrating screen, and is an effective method for analyzing and studying the screening mechanism.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH237.6

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