回转筒中散料混合均匀性实验及离散元仿真研究

发布时间：2018-05-17 16:38

本文选题：散体物料 + 离散元法　；参考：《湘潭大学》2015年硕士论文

【摘要】：散体物料是由大量离散的颗粒组成的一个复杂系统,人们的日常生活中随处可见,如粮食、药片、食盐、味精、沙子、石子等。散体物料的混合过程是应用散体物料的一个重要操作单元,在工业生产操作中处于核心工段。研究散体物料混合,提高散体物料混合的效率以及物料混合后的均匀性等是研究者们一直关注的问题。以往,大多采用实验的方法进行研究,而缺乏对物料颗粒微观运动特性的了解,对物料的混合机理尚不十分清楚。随着科学技术和计算机技术的发展,数值计算方法得到快速而广泛的应用,其中基于离散颗粒介质动力学的离散单元法(Discrete Element Method,DEM)在不断的发展和完善,在模拟这类散体颗粒运动特性方面的问题有着显著的优势。本文以沙子和石子为研究载体,通过实验研究和数值仿真的方法对沙子和石头在对在回转筒内的混合情况进行分析;研究了回转速度、物料填充率、物料投放次序以及筒体结构对物料混合均匀程度的影响,并研究了参数的优化组合。具体内容如下:(1)介绍了散体物料以及其研究现状、散体物料混合过程研究的主要内容及其研究方法;(2)通过对沙子与石子进行密度测量实验、回弹实验以及直剪实验等,测定了密度、恢复系数、摩擦系数等参数;然后对其进行V型箱和L型箱实验,观察颗粒的流动堆积过程;建立对应的离散元仿真模型,通过对比实验和模拟仿真结果,校准离散元模型中颗粒的接触参数;(3)设计了水平回转筒物料混合实验台,采用重复停机取样进行实验,设计了多个运动工况,研究回转筒转速、物料填充率、物料投放次序以及筒体结构对物料混合的影响;(4)利用离散元模拟以及正交试验设计,选取混合时间和混合后接触颗粒数率两个试验指标,研究分析了物料填充率、转速、回转筒的直径和筒体结构对物料混合的影响。
[Abstract]:Bulk material is a complex system composed of a large number of discrete particles, which is widely used in people's daily life, such as grain, tablets, salt, monosodium glutamate, sand, stone and so on. The mixing process of bulk materials is an important operation unit for the application of bulk materials, which is in the core stage of industrial production. To study the mixing of bulk materials and improve the efficiency of mixing and the uniformity of materials after mixing are the problems that researchers have been paying close attention to all the time. In the past, most of the experiments were carried out, but the microscopic motion characteristics of the particles were not well understood, and the mixing mechanism of the materials was not very clear. With the development of science and technology and computer technology, numerical methods have been applied rapidly and widely. Among them, discrete Element method based on discrete particle dynamics has been continuously developed and improved. There are significant advantages in simulating the motion characteristics of such granular particles. In this paper, the mixing of sand and stone in the rotary cylinder is analyzed by means of experimental research and numerical simulation, and the velocity of rotation and the filling rate of materials are studied. The effects of material delivery order and cylinder structure on the mixing uniformity of materials are studied, and the optimal combination of parameters is studied. The contents are as follows: (1) introducing the bulk materials and their research status, the main contents and research methods of the mixing process of the bulk materials, the density measurement experiment, the springback experiment and the direct shear experiment on sand and stone, etc. The density, recovery coefficient, friction coefficient and other parameters are measured, and then the V and L box experiments are carried out to observe the flow accumulation process of particles. The corresponding discrete element simulation model is established, and the simulation results are compared with those of the simulation results. Calibrating the contact parameters of particles in the discrete element model, a horizontal rotary cylinder material mixing test bench was designed. Repeated stop sampling was used to carry out the experiment, and several moving conditions were designed to study the rotating speed of the rotary cylinder and the filling rate of the material. Using discrete element simulation and orthogonal test design, two test indexes, mixing time and the number of contact particles after mixing, are selected to study and analyze the filling rate and rotational speed of materials. The influence of the diameter of the rotary cylinder and the structure of the cylinder on the material mixing.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ027.1

【共引文献】