Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection

摘要: The ability of clothing to provide protection against external environments is critical for wearer's safety and thermal comfort. It a function several factors, such as environmental conditions, properties activity level.Thesefactorsdeterminethecharacteristicsofthedifferent microclimates existing inside the which, ultimately, have key role in transport processes occurring across clothing. As an effort understand effect phe- nomena on overall heat structures, numerical approach was used study buoyancy-driven transfer horizontal air layers trapped impermeable in- cluded both internal flow microclimate outside layer, order analyze interdependency these flows way transported to/from body. Two-dimensional simula- tions were conducted considering different values microcli- mate thickness (8, 25 52 mm), temperature (10, 20 30 °C), velocity (0.5, 1 3 m s −1 )a nd emissivity inner surface (0.05 0.95), which implied Rayleigh numbers spanning 4 or- ders magnitude (9×10 2 -3×10 5 ). convective trans- fer coefficients obtained along found strongly depend phenomena microclimate, particular when natural convection most important mechanism. In scenario, vary wavy-like manner, depend- ing position vortices microclimate. These observations clearly differ from data literature case over flat-heated surfaces with constant (which shows monotonic variations convec- tive coefficients, length surface). patterns fields characteristics boundary layer forming distribution local rates are marked con- trast those enclosures constant-temperature active walls. results stress im- portance coupling calculation radiative components, analyzing