Since the early twentieth century, simple fibrous filters have been used as one of the main components inventilation an‎d air pollution control systems. With the advancement of technology an‎d the growing deman‎d for higher filtration efficiency, more advanced filter designs have been developed. Among these, pleated filters have gained particular importance in applications such as HVAC systems, the automotive industry, an‎d medical equipment due to their high surface-area-to-volume ratio, lower pressure dro‎p, an‎d longer service life. In this study, the performance of pleated polypropylene filters was numerically investigated using the computational fluid dynamics (CFD) method. The main objective was to analyze the airflow behavior inside the filter an‎d to predict the velocity field an‎d pressure dro‎p under the influence of geometric parameters, including pleat depth, pleat number, an‎d the permeability of the porous medium. For this purpose, three permeability levels of 7×10^(-13), 8×10^(-12), an‎d 9×10^(-11) " " "m" ^2, three pleat depths (20, 25, an‎d 30 mm), an‎d three pleat numbers (100, 180, an‎d 260 pleats per meter) were selec‎ted based on published studies an‎d data commonly used in practical filter designs an‎d were subsequently analyzed. Initially, based on a study conducted by Feng et al., a numerical simulation was performed to validate the developed model. The obtained results showed good agreement with the reported data, confirming the accuracy of the numerical modeling. After this validation step, the effects of variations in geometric parameters an‎d permeability on filter performance were further investigated. The results indicated that the velocity distribution in the transverse direction generally followed a parabolic an‎d symmetric profile, with a maximum velocity of approximately 0.20 m/s at the center of the pleats an‎d minimum values near the walls. In the streamwise direction, an increasing velocity trend from approximately 0.03–0.05 to 0.33–0.35 m/s was observed, which reflects flow acceleration under the influence of the applied pressure gradient an‎d the gradual passage of air through the porous medium. Moreover, the results demonstrated that changes in geometric parameters such as pleat number an‎d pleat depth, as well as variations in porous medium permeability, alter the hydrodynamic resistance an‎d consequently affect the pressure dro‎p. In certain cases, flow path restriction led to an increase in pressure dro‎p. Finally, it can be concluded that the optimal selec‎tion of geometric parameters in conjunction with an appropriate permeability plays a crucial role in improving filtration performance an‎d reducing energy consumption in ventilation systems.

پرهام سلطاني

مهدي حجازي , توحيد دستان