滤筒除尘器内部流场实验研究与数值模拟

发布时间：2018-03-11 07:21

本文选题：滤筒除尘器　切入点：流场均匀性　出处：《西安建筑科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：面对日益严重的大气污染问题,高效除尘器的深入研究刻不容缓。滤筒除尘器是在袋式除尘器基础上发展起来的新型除尘器,具有体积小、过滤面积大、维护施工便捷以及除尘效率高等众多优点。然而,现在国内外学者对滤筒除尘器研究较少,对滤筒除尘器内部流场特性方面的研究更是欠缺。维持滤筒除尘器内部流场良好的均匀性,可保障除尘器的使用寿命和过滤效率,具有重大的工程意义。本文系统介绍了滤筒除尘器滤筒结构、材料以及清灰方式等,通过实验测试对滤筒除尘器基本运行参数进行记录和研究。由实验测试得:覆膜滤筒运行时初始内外压差为39.8Pa,初始过滤效率在98%左右,脉冲喷吹清灰后,滤筒内外压差以及过滤效率都较之前有所提高;并且在测试过程中发现滤筒除尘器存在内部流场紊乱问题。针对实验用滤筒除尘器流场紊乱问题,本文借助于计算流体力学(CFD)相关软件以及实验中所得除尘器进出口速度、滤筒内外压差等参数,建立实验用滤筒除尘器模型。模拟分析得除尘器流场速度相对均方差值为0.43,说明流场均匀性差。为了研究导流板、气流均布板和灰斗挡风板对除尘器流场均匀性的影响,设立5因素4水平的正交试验,通过建立16种不同的滤筒除尘器模型模拟分析。研究发现:适当增加气流均布板数量C、减小其角度D以及增加灰斗挡风板长度E可有效提高流场均匀性,并且设立灰斗挡风板能防止灰斗内二次扬尘发生;调整N型风道中的导流板数量A及其角度B对流场影响甚微;影响流场均匀性各因素重要性排序为灰斗挡风板E气流均布板角度D气流均布板数量C导流板数量A导流板角度B。利用较优水平建立的新型滤筒除尘器,其流场均匀性提高了39.5%。除了上述几个因素外,进风方式也是影响滤筒除尘器内部流场均匀性的另一主要因素,为了更好地反映滤筒除尘器在下进风、侧进风及上进风三种进风方式下的内部流动情况,在之前研究基础上,本文从速度迹线、速度云图以及压力云图等因素多方位剖析除尘器内部流场,同时借助滤筒内外侧6条压力监测线分析滤筒附近流场。研究表明:三种进风方式中,侧进风滤筒除尘器流场均匀性最优、上进风滤筒除尘器次之、下进风滤筒除尘器最差,侧进风滤筒除尘器滤筒流量最大偏差(35)qiK为0.192,综合流量不均匀幅值?(35)K为0.069;侧进风滤筒除尘器与上进风滤筒除尘器内部流场具有一定的相似性,但都面临两滤筒间隙速度过高,滤筒冲刷严重问题。通过布置开孔率为30%均布板优化上进风滤筒除尘器,流场均匀性显著提高,最大流量不均匀幅值(35)qiK减小46.2%、综合流量不均匀幅值?(35)K减小了42.3%。
[Abstract]:In the face of the increasingly serious problem of air pollution, the in-depth study of high efficiency dust collector is urgent. The filter drum dust collector is a new type of dust collector developed on the basis of bag dust collector, which has small volume and large filter area. The maintenance construction is convenient and the dust removal efficiency is high. However, there are few researches on the filter drum dust collector at home and abroad. The research on the flow field characteristics of the filter drum dust collector is even less. To maintain the good uniformity of the flow field in the filter tube dust collector, the service life and filtration efficiency of the filter can be guaranteed. It is of great engineering significance. This paper systematically introduces the structure, materials and ash removal methods of filter drum dust collector. The basic operating parameters of filter tube dust collector were recorded and studied by experimental test. The experimental results showed that the initial pressure difference between inside and outside was 39.8 Pa. the initial filtration efficiency was about 98%. The pressure difference inside and outside the filter barrel and the filtration efficiency are improved, and the problem of internal flow field disorder in the filter tube dust collector is found in the testing process. In this paper, the inlet and outlet velocity of the dust collector and the pressure difference inside and outside the filter tube are obtained by means of the CFDs software and the experiment. The model of filter tube dust collector for experiment is established. The simulation results show that the relative mean square deviation of the velocity of the dust collector is 0.43, which indicates that the flow field is not uniform. In order to study the influence of the airflow distribution plate and the ash bucket windshield on the uniformity of the flow field of the dust collector, the flow field uniformity of the dust collector is studied. Set up 5 factors and 4 levels of orthogonal experiments, Based on the simulation analysis of 16 different filter drum dust catcher models, it is found that the flow field uniformity can be effectively improved by increasing the number of airflow uniform plates C, reducing the angle D and increasing the length E of the dust bucket windshield plate. The secondary dust in the hopper can be prevented by setting up the grey bucket windshield, and the influence of adjusting the number of diversion plates A and its angle B on the flow field in N type air duct is very little. The order of importance of the factors affecting the uniformity of the flow field is as follows: grey bucket windshield, E air distribution angle, D flow distribution plate number, C flow guide plate number, A flow guide plate angle B, A new filter drum dust collector, which is established by using the better level. In addition to the above several factors, the air intake mode is also another main factor affecting the uniformity of the flow field in the filter drum dust collector, in order to better reflect the lower inlet air of the filter tube dust collector, On the basis of previous studies, this paper analyzes the internal flow field of the precipitator from factors such as velocity trace, velocity cloud map and pressure cloud map. At the same time, the flow field near the filter tube is analyzed with the help of six pressure monitoring lines on the inside and outside side of the filter tube. The results show that the flow field uniformity of the sideway inlet filter is the best, the upper air filter is the second, and the lower inlet filter is the worst. The maximum deviation of the flow rate of the filter cartridge is 0.192.The amplitude of the comprehensive flow is not uniform? K = 0.069. The internal flow field of the cross inlet filter drum dust collector is similar to that of the upper air filter drum filter, but both of them are faced with excessive clearance velocity between the two cartridges. The filter tube scour is serious problem. By arranging the perforation rate of 30% uniform distribution plate to optimize the upper air filter drum dust collector, the flow field uniformity is improved significantly, the maximum flow rate uneven amplitude is 35% and the maximum flow rate uneven amplitude is reduced to 46.2%, and the comprehensive flow rate is not uniform. 35% K decreased 42.3%.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X701.2

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