基于离散元理论的振动筛分过程数值仿真研究

发布时间：2018-06-03 16:30

本文选题：振动筛 + 离散元法　；参考：《昆明理工大学》2012年硕士论文

【摘要】：本文分析了关于振动筛研究的发展情况、离散元法的相关理论以及它们的国内外的研究情况。离散元法是Cundall和Strack在1979年提出的用以研究非连续性颗粒物质结构和运动规律的一种数值计算方法,其基础是牛顿第二运动定律。由于离散元法在解决多颗粒运动分析时对计算量要求较大,对计算机硬件要求较高,所以在理论提出之初没有得到广泛的应用。随着科学技术特别是电子计算机硬件技术的不断发展以及并行运算算法的不断创新,离散元法已经可以初步应用于流体力学和相应的散体力学中,并取得了一定的成果。首先,在离散元理论中离散物质的接触模型是离散元的基础,因此本文通过对比离散元法的线性接触模型和非线性接触模型,并分析了在筛分过程中的主要研究对象的特点,选定Cundall的弹簧—阻尼—滑动接触模型作为我们主要的应用模型。其次,本文在分析了直线振动筛的运动原理以及筛分原理的基础之上编制了基于离散元法的直线振动筛筛分仿真程序,并对程序仿真过程中的离散元小球生成、离散元小球的接触判断以及离散元小球的受力计算算法做了相应的研究。并研究了程序中各执行步骤的逻辑结构以及数据结构用以提高运算效率。讨论了程序各执行阶段之间的算法的优劣。包括离散元物质的生成算法、碰撞判断算法等。对应用CUDA技术对振动筛分仿真程序的优化进行了研究。最后,本文分别仿真了单个颗粒在平面上的弹性运动、弹塑性运动以及滑动；单个颗粒在不同振动筛分参数情况下的运动特点,即不同振动参数对颗粒的速度、抛掷高度的影响；直线振动筛分过程中不同的振动参数对筛分效率的影响。并依据仿真结果给出提高直线振动筛筛分效率的方法。
[Abstract]:This paper analyzes the development of the research on vibrating screen, the theory of discrete element method and the research situation at home and abroad. The discrete element method is a numerical calculation method which is proposed by Cundall and Strack in 1979 to study the structure and motion law of the discontinuous granular material. The basis is the Newton's second law of motion. In solving multi particle motion analysis, the discrete element method has a large requirement for calculation and high requirement for computer hardware, so it has not been widely applied at the beginning of the theory. With the continuous development of the technology of the hardware and the continuous innovation of the parallel computing algorithm, the discrete element method can already be preliminary. It has been applied to fluid mechanics and corresponding granular mechanics and has achieved certain results.
First, the contact model of discrete matter in discrete element theory is the basis of discrete element, so by comparing the linear contact model and nonlinear contact model of the discrete element method, the characteristics of the main research objects in the screening process are analyzed, and the spring damping sliding contact model of Cundall is chosen as our main application. Model.
Secondly, based on the analysis of the motion principle and the sieving principle of the linear vibrating screen, a discrete element method based simulation program for linear vibrating screen sieving is compiled, and the discrete element ball generation, the contact judgment of the discrete element ball and the calculation algorithm of the force calculation of the discrete element ball in the process of the program simulation are studied accordingly. The logic structure of each procedure and the data structure are studied to improve the operation efficiency. The advantages and disadvantages of the algorithms are discussed, including the generation algorithm of the discrete element material and the collision judgment algorithm. The optimization of the vibration screening simulation process is studied by the application of CUDA technology.
Finally, this paper simulates the elastic motion, elastoplastic motion and sliding of a single particle on the plane, and the motion characteristics of a single particle under different vibration screening parameters, that is, the influence of the different vibration parameters on the velocity and throwing height of the particles, and the influence of the different vibration parameters on the screening efficiency in the linear vibration screening. Based on the simulation results, a method to improve the screening efficiency of the linear vibrating screen is given.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH237.6

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