Filtration Efficiency of Non-Uniform Fibrous Filters

It is desirable to be able to estimate the filtration efficiency of such non-uniform fibrous filters from their composition arrangement and the filtration property of individual fibers. Toward that end, we approximate the filter system as a series of cells composed of individual fibers with random distribution, deviating from the homogeneity assumption in the classical models.

With better characterization of the filter structure on the basis of the Voronoi diagram, we theoretically revisit filtration efficiency by the top-down (TD) approach and the bottom-up (BU) approach. The proposed models are compared with existing experimental and numerical results under different fiber volume fractions, indicating the high accuracy of the TD model for the filtration of submicron aerosol particles. The influence of the degree of randomness of fiber distribution on filtration efficiency is also quantified.