【作者】 朱会；

【导师】 王京刚；

【作者基本信息】 北京化工大学 ， 环境工程， 2007， 硕士

【摘要】 旋风分离器内部的流体流动为三维强旋转和高强度湍流的两相流动，流动规律非常的复杂，因此很难通过实验或解析的方法预报其内部流动状况。由于实验条件的限制，单纯通过实验来研究旋风分离器的性能不仅周期长而且费用高。目前，借助于计算机模拟技术来解决这一问题已经成为研究旋风分离器的一种重要的手段。旋风分离器内气固两相流场的模拟计算过程中涉及到许多的数学运算问题，如：网格划分、线性插值、三对角追赶法(TDMA)、代数方程的迭代解法、常微分方程初值问题的数值解以及速度分布的可视化等。解决这些数学问题的过程比较繁琐，因此选择合适的程序设计语言和数值处理软件就显得非常重要。在以前计算的过程中，我们大部分用的是FORTRAN、BASIC等语言，采用这些语言编程，最大的缺点是程序控制不灵活，语言功能不强大，尤其是涉及到矩阵计算或是图形绘制时，更显其不足。而以矩阵和数组为基本数据单元的高效的工程计算语言-MATLAB语言的出现，降低了在流场模拟中软件开发的难度。借助MATLAB软件，采用标准κ—ε模型，基于同位网格的SIMPLEC方法，对切向入口旋风分离器内的气固两相流场进行了数值模拟研究。直接调用其内置命令函数，对旋风分离器进行了网格划分，生成插值计算、三对角追赶法(TDMA)、交替方向迭代法(ADI)以及常微分方程初值问题等求解过程的函数文件和程序文件以供调用，采用while循环语句组成内迭代和外迭代运算。直接调用MATLAB绘图指令，能方便地生成旋风分离器内流场的速度、压力分布图以及颗粒的运动轨迹图。通过基于MATLAB的旋风分离器内气固两相流场的数值模拟研究，将运行结果与前人实测结果进行对比，验证了程序的可行性与准确性，揭示了旋风分离器内流场的特点：旋风分离器内的切向速度分布呈双涡结构，以最大切向速度之为界，外部是准自由涡，中心是准强制涡；轴向速度分布以零包络面为界，外部是下行流，中心是上行流；颗粒的运动轨迹比较复杂，且带有很大的随机性，尤其是小颗粒，受气流流动的影响比较显著，入射位置和颗粒粒径对其运动轨迹都有很大的影响。这些研究成果为旋风分离器的优化设计提供了一定的理论依据。更多还原

【Abstract】 There is strong 3D rotation and high-intensity turbulence of two-phase flow in the cyclone, and the flow pattern is very complicated, so it is very difficult to predict its internal flows by doing an experiment or using analytical methods. Due to the limitations of experiment, it costs long time and fare just to study the cyclone performance by doing a simple experiment. Currently, it is a very important tool to study the cyclone with the technology of simulation by computer.During the simulation process of gas-solid flow in cyclone, it involves many of the arithmetic problems, such as: mesh, linear interpolation, three diagonal multiply algorithm (TDMA), iterative algorithm of algebraic equations, the numerical solution of the non-stiff differential equations with initial conditions, the visualization of velocity distribution, and so on. It is very tedious to solve these mathematical problems, so it is very important to choose a right program language and numerical processing software. Previously, we used FORTRAN, BASIC, and other languages mostly; they are not flexible in program control and not powerful in language function, which is more obvious especially in matrix calculation or graph-showing. Now, it reduces the difficult of software development in the flow simulation, with a high efficient compute language based on matrix and array - MATLAB.The flow field in a cyclone has been simulated based on MATLAB, and the standardκ-εturbulent model and SIMPLEC method with collocated grid were used to simulate the gas-solid flow. Functions which are built-in or programmed into MATLAB were directly invoked. Within a while expression, inner and outer iterations were readily constituted and it was found to be easy to invoke the plot commands to plot figures of the velocity distribution and the particle track in a cyclone.By doing the research of MATLAB-based simulation on gas-solid two-phase flows in cyclone, the result is compared with the previous experimental result, which has validated the feasibility and the accuracy of the program, and it also reveals the characteristics of the flow field in cyclone: the tangential velocity is double vortex-external natural vortex and internal mandatory vortex, which can be divided by the maximum tangential velocity; the axial velocity can be divided into outer up flow and inner down flow; the particle trajectories are complicated with a lot of randomness, especially small particles, they are greatly affected by the incident size and location of the particle. These research results can provide a theoretical basis for the cyclone optimization design.更多还原