开口散射器对滤筒除尘清灰性能影响的数值模拟

Numerical Simulation of Influence of Opening Diffuser on the Dust-cleaning Performance of Cartridge Filters

借助计算流体力学的方法,编写自定义压力函数(UDF),采用二维非稳态流动数学模型对滤筒除尘器脉冲喷吹清灰过程进行了数值模拟,研究开口散射器锥角、安装高度、喷吹距离等因素对滤筒除尘器脉冲清灰效果的影响,为滤筒除尘器清灰系统的优化设计提供依据。结果表明:相较传统的清灰方式,增加开口散射器结构能有效改善滤筒除尘器内部清灰流场均匀性和滤筒侧壁压力分布均匀性,提高除尘效率。当开口散射器锥角减小时,清灰强度存在最大值,而滤筒侧壁清灰压力趋向不均匀化;散射器锥角一定,安装高度为0 mm时,滤筒侧壁压力峰值的平均值由853Pa增大到999Pa,偏差由2.45%降低到1.25%,既能够保证足够大的清灰强度也能使滤筒清灰均匀性得到有效改善;在其他因素不变的情况下,增大喷吹距离,滤筒清灰强度减小,清灰均匀性增大,清灰装置存在最佳的喷吹距离范围。

The numerical simulation of filter cartridge flow fields during pulse jet cleaning was carried out by means of computation fluid dynamics method,using a two-dimensional,unsteady flow mathematical model and defined pressure function（ UDF）. This investigation offers basis for the optimal design of pulse-jet cleaning of filter cartridge by studying the taper angle,the installation height,injecting distance and other factors on the dust-cleaning performance of cartridge filters. The results show that,compared with the traditional way of cleaning the blowing holes,the increase of the opening diffuser structure can improve the uniformity of the flow field inside the filter and the uniformity of the wall pressure distribution of the filter,and improve the dust efficiency. The cleaning strength has the maximum value and the filter side wall cleaning pressure tends to be nonuniform when the cone angle of the opening diffuser decreases. When the height of the diffuser is constant and the installation height is 0 mm,the average value of the pressure peak of the side wall of the filter cartridge is increased from 853 Pa to 999 Pa,and the deviation is reduced from 2. 45% to 1. 25%,which can not only ensure a large enough cleaning strength,but also make a better cleaning uniformity of the filter cartridge. In the case of other factors remaining unchanged,filter cleaner strength decreases,cleaning uniformity increases and there is the best range of blowing distance the cleaning device when the blowing distance increases.