Simulating the structure and air permeability of needle-punched nonwoven layer

The aim of this article is to study and simulate the structure of needle-punched nonwoven fabrics in order to predict air permeability of nonwoven filters. For this purpose, the Poisson's random number process has been used to model the random position of fibers in a web. A simple and easy-to-use expression was developed to predict the number of webs in a layer, considering the thickness and areal density of nonwoven fabrics. A 3D model was generated by assembling simulated webs. The GAMBIT meshing software was used to generate the mesh for the Computational Fluid Dynamic (CFD) solver. The outlet pressure of generated model was determined by means of CFD tool. Different types of needle-punched nonwoven fabrics were produced using Polyester fibers with different cross section and counts. The air permeability test was carried out on the samples, and the outlet pressure of each sample were measured and compared with theoretical values. The results showed that the simulated structure is capable to predict the air permeability of nonwoven filters adequately. The main novelty of the model is the ability of simulating the structure and air permeability of multi constituent nonwoven layers.