Study of the Dynamics of Water Droplet Freezing on the Surface of Nanocomposites in the Long-Wavelength Infrared Range

Resumo

A technique is developed to determine the freezing time, thermal resistance, heat transfer coefficient, and cooling power of water droplet on the surface of studied materials by means of video recording in the long-wavelength infrared range. These parameters are found for water droplets on a hydrophobic coating based on organosilicon polymer filled with carbon nanotubes as well as on polyethylene terephthalate film. On hydrophobic coatings the water droplets froze 1.5–4 times slower than on polyethylene terephthalate film, which is explained by an increase in the contact angle and thermal resistance between the droplet and surface of the coating. Correlation between the freezing time and thermal resistance reveals that the heat flux from the droplet towards the material surface is crucial for the freezing time. In tests, partial adiabatic droplet freezing with the following complete isothermal freezing were observed during a single freezing process. The studied hydrophobic coatings may potentially be used as anti-icing coatings.