Micro-scale layered structural filtration efficiency model: Probing filtration properties of non-uniform fibrous filter media

Motivated by modeling of the filtration of non-uniform fibrous filter media, a micro-scale layered structural based single fiber filtration efficiency (SFFE) model is developed to calculate filtration efficiency of clean fibrous filter media. A new methodology based on fractal theory, statistical theory and classical flow field theory is developed in the SFFE model. The microstructure of the four fibrous samples are resolved by the GeoDict code and included in the model. With the non-uniform SFFE model, evolution of the microscopic characteristics of the samples (fiber diameter, fiber orientation, pore size distribution, and permeability) can be probed. Based on analysis of the SEM image of the sample showed that the fiber diameter and orientation distribution were Gaussian. Results from four kinds of fibrous filter media are analyzed and compared with the simulated and theoretical values. The pore size distribution was independent of the grammage. The air permeability decreased with sample thickness, and the fluid had a fast flow velocity for large pores in the porous material. Compared with classical filtration theory, the non-uniform SFFE model show good agreement with the experimental and simulated values.