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1、东北大学硕士学位论文 摘要 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
2、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
3、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I东北大学硕士学位论文 Abstract Numerical Simulation of Temperature Field and Flow Field within Mechanical Rotary Cleaning Bag FilterAbstr
4、actIn 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 second
5、ary 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 i
6、s 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
7、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 the curve of filter bag clearance air rising velocity. Concluded by analyzing:
8、high-pressure zone occurres in the dusty gas imports, because here inlet velocity is very fast; area of low pressure occurres in the net at the air outlet, because the filter is very slow, so speed is very slow at the outlet; the penetration rate is very small, so, when the dusty gas through the bag
9、 before and after, the pressure happen to step, the air rising velocity of filter bag clearance changes smoothly and tend to uniform, so this is more conducive to the sedimentation of particles of just off from the bag by reverse blowing, short the settling time and improve the efficiency of dust re
10、moval.Change the filter velocity, the inlet velocity, the height of inlet and depth-width ratio, the founds by comparative analysis the clounds show that: the change of these parameters will not affect the bag filter internal temperature field, pressure field and velocity field distribution law, but
11、 change the magnitude of the corresponding parameters; the filtration rate and inlet velocity increasing have a serious impact on the total pressure loss; the flow distribution coefficient curve also show that: the filtration velocity and inlet velocity is more increase, the flow distribution of bag
12、 filter is more inhomogeneous, the result after the comparative analysis is that: the lower filtration velocity and inlet velocity are beneficial to the uniform flow distribution. The particle trajectory figure shows that: the particles decrease in the movement of the second lap of the filter chambe
13、r, most of the particles settle to ash bucket by the action of gravity and centrifugal force, filter bag capture only a small portion of particles on the rotary air inclusions.Keywords: bag filter; numerical simulation; filtering rate; flow distribution VII东北大学硕士学位论文 目录 目录独创性声明I摘 要IIAbstractIII目录V第1
14、章 绪论11.1 课题的来源及背景情况11.2 课题研究目的11.3 机械回转反吹袋滤器国内外研究现状21.4 研究内容和研究方法31.5 本文研究的意义4第2章 机械回转反吹袋滤器的求解模型52.1 CFD概述52.1.1 CFD基本思想与本质52.1.2 CFD发展62.1.3 CFD应用领域62.2 Fluent软件简介62.3 控制方程和求解技术82.3.1 基本控制方程82.3.2 CFD求解技术112.4 气固两相流理论122.5 多孔介质理论132.5.1 多孔介质模型132.5.2 多孔跳跃模型142.6 本章小结15第3章 气相数值模拟173.1 工作原理173.2 袋滤器的性能指标183.2.1 过滤气速183.2.2 压力损失183.2.3 除尘效率193.3 模拟参数193.3.1 处理气体流量203.3.2 进口气流速度203.4 模型的前处理213.4.1 建立计算模型213.4.2 网格划分213.4.3 设置边界条件223.4.4 参数设置233.5 模拟结果分析233.5.1 温度场结果分析243.5.2 压力场结果分析253.5.3 速度场结果分析273.5.4 湍流强度结果分析293.6 本章小结30第4章 气固分离数值模拟314.1
