Interfacial heat transfer through a natural protective fibrous architecture: a wild silkworm cocoon wall

The wild Antheraea pernyi silkworm cocoon is a thin and light-weight structure, yet it has shown effective thermal insulation characteristics against extreme temperature fluctuations, which meet the demands of humans for lighter materials with higher thermal resistance. We present a two-dimensional computational fluid dynamics model of this unique fibrous cocoon structure to simulate the heat transfer process through the cocoon wall. The model is able to predict the temperature field inside the cocoon reasonably well. The results of the model also show that the mineral crystals present in the outer layers of the Antheraea pernyi cocoon can increase air flow resistance and decrease the effect of natural convection, which further reduces the heat transfer through the cocoon wall effectively. This has practical significance for the development of thermal functional textiles and composite structures.