Research on the filtration performance of pleated filters with rectangular and triangular structures through developed CFD code

Pleated filters are widely used in industrial ventilation systems due to their large filtering area, small resistance and competitive volume. In this paper, a numerical calculation code based on CFD to calculate the flow resistance and filtration efficiency of different pleat sizes has been developed, and the accuracy of the model is also verified by experiments, and the maximum relative errors of resistance and efficiency are 3.43% and 11.09%, respectively. Based on this model, the filtration performance of pleated filters with rectangular and triangular structures is researched and discussed. The results show that the decrease of the pleat width will increase the flow resistance of the airflow inside the pleated structure, resulting in the uneven distribution of the gas velocity in the direction of the pleat height, and the higher the velocity in the direction of the pleat depth. Under the filtration velocity of 0.02 m/s and 0.1 m/s, when W = 2 mm, rectangular pleats have more uniform velocity and efficiency distribution than triangular pleats, but when W = 12 mm, the velocity and efficiency distributions are the same for both shapes, which indicates that increasing the pleat width has a more significant impact on the V-shaped pleats. In addition, it is also found that the distribution of efficiency over pleat height is related to the velocity distribution and the dominant mechanism of filtering aerosols, so the distribution of efficiency over pleats should be judged according to filtration velocity and particle size.