Numerical modeling of body heat dissipation through static and dynamic clothing air gaps

The clothing air gap between the skin surface and clothing layer plays an important role in the body heat dissipation. In this study, we built a numerical model to investigate the heat transfer phenomenon through the clothing air gap in a single layer loose-fitting garment with large air gaps. Firstly, we investigated the thermal performance of the static air gaps with closed ends and open ends, respectively, against their thickness and height at different environmental temperatures. Then, the dynamic air gaps with oscillating clothing layers were studied to examine the influence of the so called pumping effect (viz. the oscillation of clothing layer) on the heat transfer through the air gaps. The results showed that closing the ends of the static air gap (i.e. simulation of closing the openings of clothing) can double the thermal resistance when the air gap thickness is sufficiently large. On the other hand, the pumping effect, which may be caused by body motion or external forces, can halve the thermal resistance of the air gap with open ends in some conditions. This study is of great importance for the design of functional clothing for human body thermal management.