Effect of inter-segmental air exchanges on local and overall clothing ventilation

Abstract

The aim of this work is to study the effect of the connection between arm and trunk segments in changing the flow characteristics and local ventilation. A model is developed that solves coupled momentum, mass and heat balances, including buoyancy for the connected clothed upper human body. The model was validated by performing computational fluid dynamics simulations to compare the microclimate air flow characteristics and flow direction at the connections. In addition, the model was also validated by comparing predicted overall ventilation with published data. The interconnection air exchanges affected significantly local ventilation in the trunk segment and the direction of the flow in the open-aperture-clothed arm segment. It was found that at relatively high wind speed (V(w)0.9m/s) and with a permeable jacket, the inter-segmental ventilation became important and exceeded 5l/min. Meanwhile, this inter-segmental ventilation caused an increase of 15% of trunk ventilation and a reduction of 4% of arm ventilation. The inter-segmental ventilation vanished and the air exchange between the trunk and the arm was no longer important at low permeability (=0.05m/s) and at low wind speed (V-w=0.1m/s). Finally, the inter-segmental ventilation was more important for the open clothed arm aperture compared to when it was closed.