Numerical analysis of dry heat transfer in textiles and clothing microclimate

Abstract

The computational fluid dynamics approach has been widely applied to explore the comfort level of human clothing. In many studies, the human limbs and trunk are treated as a uniform cylinder, yet there is a failure to consider the uniformity of airflow velocity and temperature on the surface of clothing. This poses challenges for the testing of cylindrical fabric thermal and moisture resistance to assess clothing comfort. In this study, a 2D heat transfer model for porous textiles under different airflow and temperature conditions was established. Then, a comparative analysis was conducted of three air supply methods. The results show that the wind speed difference rates generated on the surface of the clothing by these three air supply methods were 83.3%, 65.1%, and 1.9%, respectively. To ensure that the wind speed on the surface of the clothing is as uniform as possible, method 3 was adopted to establish the wind field. In this study, the combined influences of thermal conduction, natural convection, and forced convection were incorporated to investigate the distribution of temperature and wind fields within the model, as well as the changes in clothing performance under various environmental conditions. Additionally, the microclimate between the skin and clothing directly affects human comfort. Therefore, in this study, heat transfer phenomena within the microclimate were also explored under different environmental conditions. The model in this paper is intended to provide an effective and accurate method for cylindrical fabric thermal and moisture resistance testing, to study the comfort of clothing.