Experimental and numerical investigation of heat and moisture transfer in skin-porous clothing-environment systems

Understanding heat and moisture transfer in skin-clothing-environment systems is important for improving thermal comfort and the functional performance of sportswear. Although clothing thermal performance has been widely studied, the combined effects of fabric properties, garment geometry, environmental conditions, and moisture transport are not fully understood. The objective of this dissertation is to develop experimental and numerical methods to investigate heat and moisture transfer in skin-clothing-environment systems, with fabrics represented in the numerical model as porous and air-permeable media rather than impermeable boundaries. This study combines experimental and numerical approaches. Sweating guarded hotplate experiments are used for fabric characterization and model validation, while a sweating torso is used to investigate transient responses during dry, sweating, and drying phases. Numerical models are developed for planar air gaps, wavy clothing geometries, multilayer porous systems, and torso-scale configurations. The results show that air gap thickness, orientation, and airflow direction strongly influence heat and moisture transfer. In planar air gaps, heat and moisture transfer shift from conduction and diffusion dominated transport to natural convection once a critical thickness is reached. In wavy air gaps, airflow parallel to fabric folds enhances heat transfer compared with cross flow, while fabric permeability produces a non-monotonic effect due to the transition from natural to forced convection. For multilayer clothing systems under wind, the outer air gap transitions from natural to mixed and forced convection as air velocity increases, whereas external airflow does not substantially penetrate the inner fabric layer under tested conditions. Air gap thickness distribution and fabric arrangement significantly affect total heat flux, with permeability having a stronger influence than thermal conductivity. Torso-scale experiments and simulations further show that air gaps, fabric type, moisture distribution, body geometry, garment fit, and local airflow variations create non-uniform thermal and moisture behaviour. This dissertation contributes to understanding and predicting heat and moisture transfer in clothing systems by linking porous fabric properties, air gap geometry, environmental exposure, and garment configurations. The findings clarify heat and moisture transfer mechanisms within clothing air gaps and provide guidance for the design of sportswear and functional garments with improved thermal comfort and moisture management.