Pore-scale numerical study of intrinsic permeability for fluid flow through asymmetric ceramic microfiltration membranes

摘要

The asymmetric ceramic microfiltration (MF) membrane is widely used in water treatment processes, yet the dependence of its intrinsic permeability on the microstructure parameters of different layers are not thoroughly understood. In this study, a numerical model combining the Discrete Element Method (DEM) with Lattice Boltzmann Method (LBM) is developed to simulate the fluid flow through the detailed pore structure of an asymmetric ceramic MF membrane. The model is validated by comparing the simulated pure water permeability to experimental data with an average deviation of 8% (Max similar to 25%). The simulation results show that the pore size D-50 and porosity epsilon, of the top and intermediate layers are dominant microstructure parameters that determine the membrane pure water permeability. A new asymmetric ceramic MF membrane intrinsic permeability Km as a function of D-50, epsilon and layer thickness h of both top and intermediate layers is derived. The verification of this Km correlation is conducted by comparison with experimental data and Carman-Kozeny (C-K), HagenPoiseuille (H-P) correlations, indicating the proposed Km correlation can accurately predict the membrane permeability. It provides a useful tool for a fundamental understanding of the effect of membrane microstructures on intrinsic permeability.

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