机械回转反吹袋滤器内温度场和流场数值模拟论文 大学论文.doc

机械回转反吹袋滤器内温度场和流场数值模拟 摘 要 近年来，布袋除尘器是回收微细粉尘的主要工具，随着环保要求的提高，布袋除尘器也被广泛应用。机械回转反吹袋滤器是布袋除尘器和旋风除尘器的有机结合之后新兴产物，它把除尘系统中的二级除尘变为一级除尘，这样可以减少系统占地面积，节约资源，提高系统的可靠性。 含尘气体在机械回转反吹袋滤器中的运动是复杂的三维气固两相流，测试其内部流场非常困难。随着科技的迅猛发展，通过计算机进行数值模拟来分析袋滤器流场分布技术越来越受到关注。本课题采用计算流体力学Fluent软件，选择RSM模型，设置速度入口和自由出口的边界条件，得到温度分布云图、压强分布云图、速度分布云图、湍流强度分布云图、颗粒运动轨迹图及滤袋间隙气流上升速度曲线。通过分析得出结论：高压区发生在含尘气体进口处，因为此处进口速度大；低压区发生在净空气出口处，因为过滤速度很慢，导致出口处的速度也很慢；因为滤袋渗透率非常小，所以当含尘气体穿过滤袋前后时，压力发生阶跃；滤袋间隙气流上升速度变化平稳，趋于均匀，这样更有利于被反吹气流反吹脱离滤袋的颗粒的沉降，缩短沉降时间，提高除尘效率。 改变过滤速度、进口速度、进口高度、高宽比，对比分析各云图发现：这些参数的改变，不会影响袋滤器内部温度场、压力场、速度场分布规律，只不过改变相应参数的数值大小；过滤速度和进口速度增大，对袋滤器全压损失产生严重影响；流量分配系数曲线也同时表明：过滤速度和进口速度增大，袋滤器内流量分配更加不均匀，对比分析之后得出，较低的过滤速度和进口速度都有利于流量分配均匀。颗粒运动轨迹图表明：颗粒在过滤室第二圈运动时下降幅度很大，在重力作用和离心力作用下大部分颗粒沉降到灰斗中，滤袋只捕获了被上旋气流夹杂的一小部分颗粒。 关键字：袋滤器；数值模拟；过滤速度；流量分配Numerical Simulation of Temperature Field and Flow Field within Mechanical Rotary Cleaning Bag Filter Abstract In recent years, bag filter is the main tool for recovery of fine dust, with the improvement of environmental requirements, bag filter is also widely used. Mechanical rotary cleaning bag filter is the emerging product of bag filter and cyclone after the organic integration, which makes the secondary dust in the dust removal system becomming a dust, thus reducing the system footprint conserving resources, and improving the reliability of the system. Dusty gas complex three-dimensional gas-solid flow in the movement in the mechanical rotary cleaning bag filter to test its internal flow field is very difficult. With the rapid development of science and technology, carrying on the numerical simulation by computer to analyze the flow field distribution of bag filter is the new technology which is more and more attention. This topic uses computational fluid dynamics software Fluent, selects the RSM model, sets the speed inlet and free outlet boundary conditions, gets the temperature contours, pressure contours, velocity contours, the turbulence intensity distribution of cloud images, particle trajectory and th