滤筒除尘器脉冲清灰系统的数值模拟研究

发布时间：2018-04-18 19:26

本文选题：滤筒除尘器 + 脉冲清灰　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：滤筒除尘器具有体积小、结构简单、过滤效率高等优点,目前在电力、冶金、食品、建材、矿山和化工等领域得到了广泛应用。但是由于滤筒筒径大、褶皱多等原因导致无法完全清灰,成为制约其推广及应用的一大障碍。因此对滤筒除尘器脉冲清灰机理进行研究,探索一种新型滤筒结构来解决当前脉冲清灰不完全的问题,能够进一步促进滤筒除尘器的发展和应用。本文利用CFD软件分别对滤筒除尘器喷吹管出流特性和脉冲清灰过程进行研究,最后根据研究结果,提出一种新型滤筒结构,以解决传统滤筒上部清灰不良的问题。主要得出了以下结论:(1)利用正交试验法对喷嘴长度H、喷嘴直径D、喷吹管直径Φ、喷吹压力P和喷嘴个数N各个因素对喷吹均匀性的影响进行研究,发现按照影响强弱排序依次为:DHΦPNL。其中喷嘴直径D对于喷吹均匀性的影响最为显著。(2)对某一滤筒除尘器的脉冲喷吹系统进行数值模拟研究,发现在脉冲过程中各喷嘴出流流量沿喷吹管气流方向逐渐增加,1#喷嘴流量仅为8#喷嘴的76.36%;前段喷嘴出流存在角严重的偏心问题,最大偏心角达5.18°。(3)为解决喷吹系统的偏心性和不均匀性问题,提出三种改进方案,分别为:(1)增大前段喷嘴直径,缩小后段喷嘴直径;(2)将圆柱形喷嘴替换为锥形喷嘴,并改变不同锥形喷嘴的收缩角;(3)将1~3#喷嘴替换为锥形喷嘴,并逐步调整其收缩角。通过对各个方案的研究发现,方案二和三都能解决喷吹气流的不均匀性和偏心性问题,但是从实用性来讲,方案三最佳。(4)在脉冲清灰过程中,滤筒内部静压从上至下依次达到峰值,滤筒下部静压最大,并沿高度方向逐渐降低;并且由于脉冲气流速度很大,在滤筒的上部会出现负压,导致滤筒上部清灰效果很不理想。增大喷嘴直径和喷吹压力,滤筒中下部峰值压力均有明显增加,而上部峰值压力增加很小。在喷吹压力为0.3MPa时,喷嘴直径为9mm、16mm、22mm所对应的最佳喷吹距离分别为190mm、180mm和160mm,适度增加喷嘴直径,最佳清灰距离会有所减小。(5)新型Ⅰ类滤筒改变内部填充体直径仅能增加中下部测点的峰值压力,上部测点影响很小,与传统滤筒差别不大。(6)椎体高度b一定时,随着填充体直径的增加,滤筒侧壁上中下三测点峰值压力均在增加,并且椎体高度越小,上部测点峰值压力增加的越快。并且当填充体直径a为150mm,椎体高度b为60mm,滤筒各测点峰值压力分布最为均匀,各测点峰值压力均远远大于300Pa,清灰效果最好。
[Abstract]:The filter drum dust collector has the advantages of small size, simple structure and high filtration efficiency. It has been widely used in the fields of electric power, metallurgy, food, building materials, mining and chemical industry.However, due to the large diameter and many folds of the filter tube, the ash can not be removed completely, which is a big obstacle to its popularization and application.Therefore, the research on the mechanism of pulse cleaning of filter drum dust collector and the exploration of a new type of filter tube structure to solve the current problem of incomplete pulse ash removal can further promote the development and application of the filter drum dust collector.In this paper, CFD software is used to study the characteristics of the blowpipe flow and the pulse cleaning process of the filter tube respectively. Finally, according to the research results, a new type of filter tube structure is proposed to solve the problem of bad cleaning in the upper part of the traditional filter tube.The main conclusions are as follows: (1) the effects of nozzle length H, nozzle diameter D, nozzle diameter 桅, injection pressure P and the number of nozzles N on the uniformity of injection are studied by orthogonal test. It is found that the order of influence is: h 桅 PNL.The influence of nozzle diameter D on the injection uniformity is most significant. (2) the numerical simulation of the pulse injection system of a filter drum precipitator is carried out.It is found that in the pulse process, the flow rate of each nozzle increases gradually along the direction of the air flow of the nozzle, and the flow rate of the nozzle is only 76.36 of that of the 8# nozzle, and there is a serious eccentricity problem in the outlet flow of the front nozzle.In order to solve the problem of eccentricity and inhomogeneity of the injection system, three kinds of improvement schemes are put forward, one is to increase the diameter of the front nozzle, and the other is to reduce the diameter of the rear nozzle. (2) to replace the cylindrical nozzle with the conical nozzle,The shrinkage angle of different conical nozzles is changed.It is found that both scheme two and three can solve the problem of non-uniformity and eccentricity of jet flow, but from the practical point of view, scheme three is the best one in the process of ash removal.The internal static pressure of the filter tube reaches the peak value from top to bottom, and the pressure of the lower part of the filter tube reaches the maximum and decreases gradually along the direction of height, and because of the large velocity of pulse flow, the negative pressure will appear in the upper part of the filter tube, which leads to the unsatisfactory cleaning effect of the upper part of the filter tube.When the nozzle diameter and the injection pressure are increased, the peak pressure in the middle and lower part of the filter tube increases obviously, but the peak pressure in the upper part increases very little.When the injection pressure is 0.3MPa, the optimum injection distance is 190mm 180mm and 160mm when the nozzle diameter is 9mm / 16mm / 22mm, which increases the nozzle diameter moderately.The optimum ash removal distance will be reduced. 5) the new type I filter tube can only increase the peak pressure of the measuring point in the middle and lower part by changing the diameter of the inner infill, and the influence of the upper measuring point is very little, which is not different from that of the traditional filter tube, and the vertebral body height b is fixed.With the increase of filling diameter, the peak pressure of the three measuring points on the lateral wall of the filter tube increased, and the lower the height of the vertebral body, the faster the peak pressure of the upper measuring point increased.When the filling diameter a is 150 mm and the vertebral body height b is 60 mm, the peak pressure distribution of each measuring point of the filter tube is the most uniform, and the peak pressure of each measuring point is far greater than 300 Pa. the ash removal effect is the best.
【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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