| As a kind of dust removal device,Bag filter is widely used in industrial dust removal,which have the advantages of simple structure,high dust removal efficiency and have no restriction on the dust specific resistance.However,it was found that bag filters have problems of premature wear and even failure of some filter bags due to the uneven flow distribution through investigation,which caused the dust removal efficiency is dropped and the operating cost is increased.Thus,it can be seen that the flow distribution uniformity of the bag filter has an important influence on the life of filter bags and the overall performance of the dust removal system.In this paper,the under-inlet bag filters are selected as the research object.Theoretical analysis and numerical simulation method are used to study the characteristics of the three-dimensional flow distribution inside the bag house,and the reason for the uneven flow distribution in the under-inlet bag filters is revealed,structural optimization project is proposed on the above analysis,to achieve the purpose of uniformity of flow distribution inside the under-inlet bag filters.The main research work and conclusions of this paper are as follows:(1)The flow field of the under-inlet bag filter was simulated by numerical simulation method,and results showed that,for the under inlet bag filter,due to the high air inlet velocity,there is a significant jet at the air inlet,and the air flow is mainly concentrated at the rear wall of the air inlet,the flow distribution is extremely uneven inside the bag filter,resulting in excessive load on the filter bags near the rear wall surface away from the air inlet,caused problems of premature wear and even failure of some filter bags,resulting in the dust removal efficiency is dropped and the operating cost is increased.So,it is necessary to optimize the structure of the bag filter to improve the uneven distribution of the flow field caused by the inlet jet.(2)Based on the flow field distribution characteristics of under inlet bag filter and aiming at realizing the uniformity of flow field distribution,the optimization measures of adding flow guide devices in dust hopper and widening of the air inlet are proposed.For the optimal solution of adding flow guide devices,the method of “equalizing the thickness of the jet caused by the high velocity of air inlet” was proposed to physically divide the inlet jet to determine the form,position and geometric dimensions of guide devices;and for the optimal solution of widening the air inlet,the results showed that the lateral width of the air inlet is positively correlated with the uniformity of flow distribution inside the bag filters.(3)The uniformity of the flow field distribution and the pressure drop of the bag filter are taken as the evaluation criteria,the optimization effect of the optimal structure proposed by this subject is compared with the flow guiding device used in the actual project.The results showed that the addition of vertical guide device in the dust hopper improves the flow distribution uniformity in the bag filter,which is better than adding the flow equalizing plate in the dust hopper,and the running resistance is reduced by 17%.(4)The numerical calculation method was used to study the effect of the addition of guide devices on the pressure drop of the bag filter.The results showed that the addition of the diversion device caused an increase in the partial resistance of the hopper(2.2%),and on the other hand caused a large decrease in the pressure drop inside the middle box(10.5%)due to the significant improvement of the distribution uniformity of the flow field.It can be seen that adding the flow guide devices reduced the total pressure drop of the dust collector(8.3%)while improved the uniformity of the flow field. |
PDF Full Text Request