Aerosol filters—Pore size distribution in fibrous filters

Abstract

A fibrous filter has been depicted as a random array of cylinders transverse to flow direction. Properties of the resulting aggregate of interlocking pores are evaluated. To this end a Monte Carlo technique is applied to generate an isotropic random line array; it could be proved that properties derived for this mathematical line model, retain their validity for actual filters. The logarithmic—normal distribution function is shown to be representative for the distribution of the surface areas of the poles and of their hydraulic radii. The geometric standard deviations of both distributions are independent of the number of fibres per unit of filter area. Expressions could be established for the geometric mean hydraulic radius and for the number of pores per unit of filter area.