Multiphase flow and moisture transport in thermophysiologically functional knitted fabrics

This study presents an integrated framework combining experimental testing, multi-criteria decision-making, digital twinning, and multiphase flow modelling to develop thermophysiologically functional knitted fabrics tailored for individuals with sensitive skin, particularly those with Atopic Dermatitis (AD). A clinically guided TOPSIS method, with AD-specific weightings, was employed to identify the top five performing configurations characterised through standard comfort-related tests, including air and water vapour permeability, porosity, fabric thickness, and wicking behaviour. These high-ranking fabrics were then subject to advanced transient multiphase flow and moisture transport analyses using the finite element method (FEM), based on high-fidelity digital twin representations of plain jersey, rib, and interlock knitting patterns. The simulations, which incorporated real-life climatic conditions, allowed for the virtual characterisation of flow, heat, and moisture transport through the porous knitted structures. The results were validated against experimental benchmarks, confirming the predictive capability of the models. Upscaled fabric level simulation results reveal that both structure and fiber material significantly influence the thermophysiological comfort, highlighting the performance of Plain Jersey-Umorfil® Vis type fabrics, and that digital twinning combined with homogenisation method offers a powerful tool for performance optimisation and scalable textile development.