Abstract: "The heat and moisture comfort performance of clothing is affected by many aspects, including objective factors such as the current ambient temperature, humidity, and wind speed, as well as subjective factors like human psychology. Additionally, traditional research on the heat and moisture comfort performance of fabrics mostly adopts the experimental detection method. However, due to the complexity of the fabric structure, this method finds it difficult to replicate the heat and moisture coupling transfer effects that occur within fabrics in real environments and even more challenging to observe heat and moisture transfer phenomena in dynamic situations. In this paper, the finite element simulation method is employed to study the heat and moisture coupling transfer process and phenomena in cotton yarn weft plain knitted fabrics when there are temperature differences and relative humidity differences between the internal and external environments of the fabric. The research combines sophisticated three-dimensional modelling with multi-physical field coupling simulation technology to reveal that heat within the fabric system preferentially transfers through the looped and interlocked regions, while static air components effectively delay heat loss, maintaining a comfortable temperature on the human skin surface. When moisture on the surface of the human skin diffuses to the outside air, it is preferentially absorbed by cotton yarn fibers until saturation before being transferred to the external environment. Therefore, the moisture diffusion rate of static air components is relatively high. A theoretical and experimental method is provided for an in-depth understanding of the heat and moisture coupling transfer process and phenomena within weft plain knitted fabrics. The results show that when there are temperature and humidity differences between the internal and external environments of the fabric, the heat and moisture transfer of the fabric microenvironment reaches dynamic equilibrium at t=234.0 s and t=264.0 s, respectively. When the heat and moisture coupling simulation model of the plain knitted fabric reaches dynamic equilibrium in heat and moisture transfer, the average temperature of the fabric microenvironment is 28.81 ℃, with a relative humidity of 51.25%. The comparison between the simulated thermal resistance of the fabric system and experimental data shows an error of 2.3%, and the comparison error for simulated moisture resistance is 4.2%. These findings validate the effectiveness of the heat and moisture coupling simulation model for plain knitted fabrics and confirm the high accuracy and good fit of the finite element simulation method. By applying finite element simulation technology to the analysis of coupled heat and moisture transfer in fabrics, researchers can quickly obtain the effective heat transfer and moisture transfer characteristics of knitted fabrics under various environmental conditions, even with limited experimental resources. This significantly reduces experimental costs and enhances work efficiency. Furthermore, the research provides a theoretical foundation for exploring the optimal design of clothing materials. In the future, this method can be further extended to other types of fiber materials and fabrics with different weaves, to investigate their effective heat and moisture comfort performance under diverse environmental conditions."

Key words: 棉纱纬平针织物, 三维几何模型, 热湿耦合传递, 有限元仿真模拟技术