Theoretical and Experimental Estimation of Inter-Segmental Clothing Ventilation and Impact on Human Segmental Heat Losses

Air exchange between a specific garment and the environment could occur 1) through the fabric with the environment, 2) through garment apertures with the environment, and 3) between local body parts’ microclimates. The first mechanism is related to the fabric properties and the flow characteristics around the human body. The second mechanism is induced by buoyancy and pressure alteration due to external wind. The third mechanism named inter-segmental ventilation occurs between different clothing sections caused by position of apertures, relative wind, fabric permeability and microclimate size of connected clothed segments. The objective of this work is to develop a simplified accurate model that solves coupled momentum, mass and heat balances including buoyancy for the connected clothed upper human body to predict inter-segmental ventilation and assess its impact on the air flow characteristics in the microclimate layer and on local ventilation rates. This model is coupled to the bioheat model to predict the effect of the inter-segmental ventilation on the heat losses from the body and on bringing the thermal comfort. The model is validated by performing an improved experimental method on a thermal manikin using the tracer gas method at different wind speeds for permeable clothing.