Thermodynamics of aerogel-treated nonwoven fabrics at subzero temperatures

Abstract

Nonwoven fabrics and aerogel have complementary properties required for good thermal insulation. In this work, the polyester/polyethylene nonwoven thermal wraps treated with amorphous silica aerogel are studied and characterized with regard to thermodynamical properties at subzero temperatures. The characterization of physical structure was done by scanning electron microscope. C-Therm TCi thermal conductivity analyzer was used to measure thermal properties like conductivity, resistance, and effusivity at subzero temperatures. Heat transfer caused by convection through the thermal wraps was measured by particle image velocimetry technique, which allows obtaining information about the current distribution of velocities in two-dimensional array in a flowing fluid. Vector and scalar maps of the fluid flow were caused by thermal convection. The samples were studied for different temperature gradients. On scientific evaluation of results, thermal conductivity and thermal effusivity were found to be differing with respect to different temperatures and fabric density. Thermal resistance showed an increase as the fabric thickness increases. It was observed that fabric density and the aerogel present in the structures have a significant effect on thermal properties of aerogel-treated nonwoven fabrics. The findings in this study are significant and can be used for further research in aerogel-treated nonwoven fabrics.