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Fibrous media are widely used in particle filtration. However, few studies have investigated the performance of fibrous media with bimodal and dense-sparse structures. In this study, computational fluid dynamics technology was adopted to simulate the filtration performance of fibrous media. A two-dimensional random multifiber distribution model was proposed based on VC++ and ICEM. Reliability was verified by comparing the model with the empirical formula. The filtration efficiencies and quality factors of submicron particle capture within different fiber arrangements, inlet velocities, and particle diameters were determined. Finally, the mechanism for improving the filtration efficiency of multi-fiber for submicron particles was analyzed. The results showed that, as the particle diameter and inlet velocity increased, the filtration efficiency and quality factor of the different fibrous media decreased, and tended to be similar. The fibrous media combined with bimodal and dense-sparse structures had the highest quality factor owing to the placement of the bimodal structure on the windward side and ratio of coarse to fine fibers.

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In this work, an existing method of capturing Fe-based fine particles by magnetic fiber is improved, and a weaving method for the fiber filter material is further determined. Different combinations of magnetic fields could form around the magnetic fibers, which change the interaction between orthogonal magnetic fibers when a uniform magnetic field is applied along the X-, Y-, and Z-axes. Therefore, the process of particle capture by the orthogonal magnetic fibers under three configurations was compared using the computational fluid dynamics-discrete phase model (CFD-DPM) and a special user-defined function (UDF) of the magnetic force. The results show that the interaction between orthogonal magnetic fibers could either inhibit or promote the capture of Fe-based fine particles by adjacent magnetic fibers. In industrial production, the magnetic filter material is suitable for the weaving method for the alternate use of magnetic and traditional fibers. When a uniform magnetic field is applied along the X-axis, this weaving method makes the capturing performance of orthogonal magnetic fiber best. Moreover, the magnetic characteristics, flow characteristics, and combination sequence of magnetic fields should be considered. This study provides scientific researchers with new insights for the development of novel high-efficiency fibrous filters to reduce particulate pollutants emissions.

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