Microstructure and particle filtration behavior of multimodal filter media made of fibers of different shapes for automotive engine intake application

This article describes microstructure of needle-punched nonwoven filter media comprising polyester fibers of different cross-sectional shapes and reports on their dynamic particle filtration behavior both at clean and clogging stages. The multicomponent fibrous filter media were characterized by their mean fiber shapes which were related to those of the individual components weighted by the corresponding mass fractions. In such media, the fibers of different cross-sectional shapes produced a synergistic effect on the gravimetric filtration efficiency at the clean stage. The fractional filtration efficiency was quite accurately expressed as a sum of fractional filtration efficiencies of individual components weighted by their surface area fractions. The evolution of pressure drop was explained in light of drag theory, and the role of fiber shape in determining the drag coefficient was discussed. Overall, the multimodal fibrous filter media prepared with fibers of different cross-sectional shapes showed a high potential for automotive engine intake application.