Numerical analysis of the flow and heat transfer in cylindrical clothing microclimates – Influence of the microclimate thickness ratio

摘要: Abstract Clothing microclimates, i.e. the space between skin and clothing, can play a central role in heat mass exchanges from or to body. This is especially true for protective where microclimates are generally thicker natural convection more likely occur. We used computational fluid dynamics approach perform numerical studies of flow transfer across cylindrical clothing Reynolds number 3900. Transient simulations were performed three different values microclimate thickness diameter ratio (0.05, 0.10 0.25), considering two-dimensional cross-section human limb surrounded by porous fabric exposed cool external air ( 10 ° C ). The obtained local along shows that increasing 0.05 0.25 decreases convective fluxes up 100 % upstream regions microclimate, increases them 190 downstream regions. asymmetry, which indicates an increasingly important as increased, often overlooked space-averaged approaches due opposite changes microclimate. Local variations temperature outer significant, reaching 14 K 90%, respectively. critical above should not be ignored was found 0.1 (e.g. corresponding thicknesses 11 mm 8 mm, around upper arm forearm, respectively).