Investigation of the particle-loaden filtration performance for real fibre media using CFD-DEM

In this paper, the particle-loaden filtration of real fibre media was numerically studied using computational fluid dynamics (CFD) and discrete element method (DEM) method. The filtration performance was comprehensively analysed by combining fluid and particle properties into a single dimensionless number, Stokes number ($St$). The results indicated that the capture efficiency increased with $St$ until it stabilised at a certain limit value, which was in good agreement with the results of the previous empirical laws, confirming the accuracy and reliability of the CFD-DEM algorithm. In addition, the capture contribution of fluid and particle properties were investigated. It was found that increasing particle size and density was effective in improving capture efficiency. Moreover, reducing fluid viscosity was the most favourable condition for improving filtration performance. For the dynamic filtration of particle size $d_p=$ 2–4 μm, the evolution of the capture efficiency and the pressure drop for $d_p$ = 4 μm was higher than that of other particle sizes due to the easy formation of the dendrite structure. In terms of the quality factor, the fibre layer exhibited a better filtration performance for particles with a diameter of 4.0 μm. This study provided a good understanding of dynamic particle-loaden filtration, which is useful for the optimal design of fibre filters.