Study of influencing factors of magnetic air filters applied in subway systems

Abstract

In the subway system, a high concentration of iron particles can cause significant damage to human health, and magnetic filters that efficiently filter out iron particles have attracted considerable attention recently. Therefore, it is both urgent and important to study the influencing factors of magnetic filters for improving filtration efficiency and reducing resistance. In this paper, to establish a filtration model for magnetic filters, the flow field, magnetic field and particle tracking of magnetic filters are calculated in three steps. After the force analysis of particles, it can be concluded that the particle tracking module needs only to consider drag force, magnetic force and gravity.

Based on the filtering model, a two-dimensional magnetic filter was simulated on a computer. and the factors affecting filtration efficiency and resistance were analyzed. It was found that an increase in magnetic field intensity and the diameter of the particle have a positive effect on the filtration efficiency of the magnetic filter, while the increase in airflow velocity and the distance between magnets has a negative effect. The increase in distance between magnets has a negative effect on the resistance of the magnetic filter. In particular, the distance between magnets and the strength of magnets are two of the most influential factors. Finally, two simple formulas concerning the relationship between filtration efficiency, resistance and influencing factors were revealed, by which filtration efficiency and resistance in practical magnetic filter design can be calculated.

Copyright © 2023 American Association for Aerosol Research

Graphical Abstract

Editor:

• Se-Jin Yook

Disclosure statement

No potential conflict of interest was reported by the author(s).