Prediction of air permeability and effective thermal conductivity of multifilament polyester yarn by finite element analysis

The effective thermal conductivity and air permeability of a multifilament polyester yarn used in sports T-shirts was investigated by computer modeling using finite element analysis (COMSOL Multiphysics, ABAQUS/CAE). It has been shown that the number of fibers, the porosity of the yarn and the proportion of fibers in the volume fraction of the yarn have a direct effect on the effective thermal conductivity and air permeability of the multifilament yarn. It was found that with the increase in the number of fibers, the porosity of the yarn decreases linearly, while the volume fraction of the fibers in-creases, and thus the effective thermal conductivity increases. In addition, air permeability decreases exponentially.