3D Dynamic Modeling Of The Pleated Air Filter Media And Simulation Of Its Performance Using CFD-DEM

There are a lot of suspended particles which do harm to human health in the outdoor air, the concentrations of indoor particulate matter are affected by the outdoor air, and people spend most of the time in indoor room, with the enhancement of ambient air quality standards and consciousness of environmental protection, it is very important to choose a suitable air filter to effectively improve the indoor air quality. Pleated air filter, because it has large filter area, low resistance, and high efficiency, has been widely used in building ventilation and air conditioning system.Therefore, the research on the filtration performance of the micro air filter media can provide the basis for the optimization of pleated air filter.The control algorithm of the pleated air filter media modeling had been designed based on the actual electron microscope image of filter media, and considering the fiber bending, deformation, penetration, arrangement, through the dynamic control of the parameters, such as the pleated angle(?), fiber layers(M), diameter(D), pleat spacing(L), number of fibers(N), curvature (c), and the designed pleated model is more similar to the actual filter media. On the basis of the above work, the software of 3D dynamic modeling of the pleated air filter media was developed, and CFD-DEM coupling method was used to simulate the dust filtration in the pleated filter media,the influence of different paramenters on the filtration performance had been analyzed.The results show that:(1) In this study, the micro structure of the pleated air filter media was established, which is very similar to the actual air filter media, and greatly simplifies the modeling work, provides the basis for the study on the dust performance of the pleated air filter media.(2) The pleating angle, inlet velocity, particle size and dust filtration performance had been analyzed respectively using the CFD-DEM coupling method. The pressure drop and filtration efficiency values were compared with theoretical analysis results,and the overall trend is consistent, which shows that it is feasible to use CFD-DEM to study the filtration performance of the pleated air filter media.(3) The dust filtration in different pleated angles, partial pressure drop of pleated air filter media (pressure drop in the thickness direction) increases with the increase of pleated angle. In addition, the partial pressure drop also increases with the increase of inlet velocity. Pressure drop presentes a nonlinearly increasing trend with the increase of deposited particles. For a given number of particles, in the filtration process, the number of particle collision increases first and then decreases with the filtration time,and the total force on geometry increases with the filtration time due to particles'weight and force from fluid, the total energy loss of collision presentes the same trend,which means a positive correlation between the loss of kinetic energy and particle collision.The deposited phenomenon is apparent in the zone where the angle between fiber axis and air flow direction is large, and this phenomenon is more apparent in the penetrated region of fibers, which indicates that fiber arrangement has an important effect on the morphology of deposited particles.(4) When the pleated angle ? is 35° and dp is less than 3?m, the filtration efficiency is low, but the filtration efficiency increases significantly with the increase of particle size, on the contrary, when dp is greater than 3?m, the filtration efficiency is high, but the increasing trend is not obvious. Compared to the particle size, the increased filtration efficiency caused by pleated angle is not significant.