Numerical modeling for particulate flow through realistic microporous structure of microfiltration membrane: Direct numerical simulation coordinated with focused ion beam scanning electron microscopy

Abstract

In this study, the focused ion beam scanning electron microscope (FIB-SEM) technique is utilized to obtain a realistic microstructure geometry of mullite and α-alumina membranes, which are commercially available microfiltration (MF) membranes, for implementation in a high-resolution numerical simulation model based on coupled direct numerical simulation (DNS) and the discrete element method (DEM). The flow and particle permeation through the membrane pores are evaluated for different particle sizes. The developed simulation model is a powerful tool for enhancing our understanding of the MF process because it introduces the realistic microporous structure of an actual MF membrane rather than the simplified membrane model structures such as straight cylindrical pores and particle packing structures that have been used in previous numerical studies. The application of the developed model is discussed for the prediction of the rejection curve, which shows the importance of considering a realistic microporous structure for the accurate prediction of the MF process. The results showed different rejection curves for the mullite and α-alumina membranes, which mainly contributed to the difference in the local pore size distributions of the two membranes. Furthermore, detailed particle permeation through the membrane is evaluated, which is not feasible in experimental analyses for realistic MF membranes. • Realistic microfiltration geometry was obtained using FIB-SEM technique. • High resolution DNS-DEM was developed for detailed particle permeation analysis. • Different rejection curve for mullite and α-alumina membranes was obtained. • Membrane microstructure affected the particle permeation behavior and rejection. • Image analysis of microstructure supported the DNS-DEM results.