Study On Numerical Simulation Of Internal Flow Field Of Bag Filter

Bag filter,as a necessary and efficient dust removal equipment in the dust removal process,has the characteristics of high dust removal efficiency and stable operation,but the airflow distribution is unreasonable and the filter air velocity in the bag area is too high.After a period of operation,the surface of the filter bag will be scoured and the replacement of the filter bag will be frequent,which does not meet the requirements in terms of economy and environmental protection.Therefore,the inside of the bag filter is unreasonable.The analysis and research of flow field is very important.Firstly,a physical model of the downward air bag filter is established,which is in accordance with the size of the reference test data model,and is simulated and analyzed by fluent simulation software.Firstly,the filter air velocity in the bag area is analyzed.Through the analysis of the filter speed in eight bags and four positions of each bag,the uniform distribution of the air flow and the drop of the dust collector are explained.The importance of low airflow velocity.Secondly,the experimental data of four rows of measuring points and eight measuring points in each row on four z-axis sections are compared with the simulation data,and the relative error is within the allowable range,which verifies the accuracy of the selected model and boundary conditions.After that,the physical model was modified based on the previous model.The lower air intake was changed to the side air intake.The entrance horn of the dust collector and the double-layer air distribution board were added,and the discrete phase model was used to make the simulation more practical.By changing the position of the two-layer air distribution board in the entrance horn,the physical models with the same opening area and different positions of the two-layer air distribution boards were established.The model is used for numerical simulation.The velocity nephograms of the first row of filter bags where the dust-laden airflow just touches the cross section of the first row of filter bags,i.e.x=0.56 m,and the velocity polygons of four groups of z-axis data under x=0.56 m are compared and analyzed.After that,the flow distribution coefficients of 16 filter bags under five kinds of double-deck air distribution boards were sorted out,and the maximum uneven flow amplitude was obtained and analyzed.Relevant conclusions are drawn about the influence of the position of air distribution plate on the internal flow field of bag filter.Finally,by analyzing the trajectory of four different particle sizes in the dust collector with double-deck air distribution plate,the corresponding particle sizes in the bag dust collector were obtained.Then the physical model of five single-layer airflow distributor with the same opening ratio is established,and the numerical simulation is carried out.The flow distribution coefficient and the maximum flow uneven amplitude are calculated to analyze the airflow distribution,and the best single-layer airflow distributor position for 16 filter bags is obtained.The particle trajectories under different single-layer airflow uniform plates are analyzed,and the corresponding conclusions are drawn.