Evaluation the effect of fiber alignment on particle collection performance of mechanical/electret filters based on Voronoi tessellations. (6th April 2019)

• Record Type: Journal Article
• Authors: Cai, Rong-Rong; Lu, Hao; Zhang, Li-Zhi
• Is Part Of: Chemical engineering science. Volume 197(2019)
• Page Start: 109
• Page End: 119
• Publication Date: 2019-04-06
• Subjects: Filtration performance -- Electret filter -- Voronoi tessellation -- 3D fiber orientation; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2018.12.015
• Languages: English
• ISSNs: 0009-2509

Abstract

Graphical abstract: 3D virtual fibrous filters with different alignment degrees (a) and their filtration performance considering electrostatic attraction (b). Highlights: 3D filters with varying fiber alignments are generated using Voronoi tessellation. Effect of fiber orientations on performance of mechanical/electret filters is disclosed. Higher degree of 3D fiber isotropy results in higher permeability. Isotropic structure of fiber networks improve the filtration performance of electret filter. Effect of fiber orientations on different collection mechanisms is compared and evaluated. Abstract: The effect of fiber alignment on particle collection performance of mechanical/electret filters are investigated numerically. Four sets of fiber networks, namely, nearly isotropic, aligned, highly aligned and layered orientations are constructed using Voronoi tessellations. The particle transport and deposition process in these fiber networks under the coupling of flow field and electrostatic field are modeled using hybrid lattice Boltzmann Lagrangian method. The particle collection efficiencies and pressure drops of the mechanical/electret filters are calculated and compared. Results indicate that the mechanical filter with layered networks has the best filtration performance for large particles, and then the aligned networks has the next best performance. However, the sequence reverses when filtering the nanoparticles. In contrast to a mechanical filter, the electret filter with isotropic networks exhibits the best performance for full range of particles size, indicating that the dielectric attraction is less impacted by the 3D fiber orientations. Increasing fibers orientations in the airflow direction and constructing 3D pores of high sphericity are recommended to improve the performance of an electret filter.