Use of air permeability for determination of equivalent average pore diameter in woven fabrics

Abstract

Scientific description of porosity/inner porous structure of textile fabrics is very complex mater and usually is made through description of so called porosity parameters. In general these are the size, number and distribution of pores in textile fabrics. Woven fabrics are the easiest case comparing them with knit and nonwovens fabrics since their structure is closer to any model representing textile fabrics. In spite many methods for determining porosity parameters no method is giving the full range of necessary results. The paper is dealing with introduction of newly developed method for determining equivalent average size of pores in woven fabrics. Equivalent average diameter of pores is defined as diameter of certain number of cylindrical pores that allow the same air permeability as real woven sample with the same number of pores (macro pores). It gives the real correlation with air permeability taking in account all characteristics of pores that participate in loose of energy i.e. the length of pores, their structure, their tortuosity and their bottle necks. The method combined with geometrical, porosity parameters determined by planar structure of woven fabrics can give connection between them and better understandings of porous structure in connection with its transmission properties.