Heat transfer simulation through textile porous media

Abstract

Over the last decade, modelling of heat and mass transfer through textile materials has become a constant focus of researchers, the research being directly influenced by the development of computer systems. The importance of the heat transfer properties of clothing is particularly crucial in high-risk professions, such as firefighters and military, or in sportswear and healthcare. While some analytical and numerical models have been developed regarding these materials, most approaches are at the macroscopic level, where microscopic details are filtered out to reduce numerical and physical complexity. When the unsteady transfer occurs, the results can have significant errors. On the other hand, simulation is a cheaper method to obtain the static or dynamic characteristics of porous materials. This paper aims to model a simple textile structure and to perform a heat transfer simulation using Comsol Multiphysics®. Comsol Multiphysics® is a software that allows the simulation of physical phenomena using geometric models. By applying the standard boundary conditions, a comparison between the simulated and experimental values was made. To have a significant result for the entire system, the dimension of the sample was chosen so that it becomes a Representative Elementary Volume. Starting from the characteristics of the yarns and a geometric model of the textile structure, by simulation has been achieved the global characteristics of the material such as thermal resistance, porosity, heat flux and relative times for which the transfer becomes stationary. Global values were obtained by the volumetric average method using predefined functions in Comsol Multiphysics®.