Effect of local densification of ultra-long filter bags on the distribution of filtration velocity on the surface of filter bags
Aiming at the problem that the filtration velocity on the surface of the ultra-long filter bag is extremely unevenly distributed along its axial direction,a numerical simulation method is used to explore the influence of local densification of the ultra-long filter bag on the filtration velocity distribution to find a solution to improve the filtration performance of the ultra-long filter bag filter.Firstly,the characterization parameters of local encryption are determined by theoretical analysis,and then the specific simulation conditions are designed.Finally,the appropriate indexes are selected to evaluate the uniformity of filtration velocity distribution on the surface of the filter bag.The results show that when the ultra-long filter bag is not locally densified,the filtration velocity on the surface of the filter bag decreases from top to bottom along its axial direction.The maximum filtration velocity is as high as 3.18 m/min(the design filtration velocity is 1.0 m/min),and the corresponding filtration velocity distribution uniformity index is 0.122.The distribution of filtration velocity is extremely uneven.Besides,the top of the filter bag is scoured by high-speed airflow.When the 30％length of the filter bag at the top of the ultra-long filter bag is locally densified,the uniformity of the filtration velocity distribution on the surface of the filter bag is significantly improved.When the local densification porosity decreases from 85％to 60％,the uniformity index of filtration velocity distribution on the surface of the filter bag increases from 0.037 to 0.518 and then decreases to 0.434,and the corresponding dust removal efficiency is not affected.When the local densification porosity is 65％,the maximum filtration velocity on the surface of the filter bag is reduced to 2.1 m/min,and the uniformity index of the filtration velocity distribution reaches the maximum value of 0.518.
safety and hygiene engineering technologybag filterultra-long filter bagslocal densificationfiltration velocityuniformity
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