Effect of Clothing Opening on Heat Transfer of Exposed Skin Measurements by Simulated Skin

It was revealed by experiments using a thermal manikin that the openings of a clothing affects the heat transfer from an exposed skin part of a human body as well as that from a skin portion covered with clothes. Contrary to the covered skin part, the heat transfer coefficient was larger when an opening was closed than when one was open, for both of the upper and lower openings. Because the effect of convection on the heat transfer of the exposed body was considered, isotherms were visualized on a hot-plate-skin-model by means of the Mach-Zehnder interferometry. When cold air outside flows into the boundary layer around the exposed skin, the temperature gradient becomes narrower compared with that without air inflow. The results verified that cold air outside flowed into the boundary layer around the exposed skin in the case where the openings were closed. Only the air near the exposed skin was heated locally, which caused a decrease in the air density; therefore cold air outside flowed into this layer. On the contrary, in case where the upper opening was open, warm air which was heated by the covered portion flows upwards and heated the cold air around the exposed part. These are the reasons for the fact that the heat transfer coefficient of the exposed skin without opening was larger than that with opening.