A novel technique for obtaining quantitative infrared-thermography data on metallic (e.g., aluminum or steel) wind-tunnel models is developed. The methodology incorporates a matte-black, thin, wrap-film (3M exttrademark Wrap Film Series 1080), which is both commercially available and relatively inexpensive. Compared to painting the model to increase the surface emissivity, using a self-adhesive thin film makes it easier to obtain uniform thickness and roughness and is easier to apply and remove. The relevant surface properties (i.e., thickness, roughness, and directional emissivity) and thermal properties (i.e., thermal conductivity, specific heat capacity, and thermal diffusivity) of the wrap film have been measured and are reported. The high emissivity (0.95) and low thermal conductivity (0.23 W/(m K)) make it an excellent candidate for quantitative infrared-thermography. Using the experimentally measured properties, and the reported data-reduction techniques, stagnation-point heat flux was successfully measured on a blunt 7∘ half-angle circular cone in nominally Mach-6 flow. Fay & Riddell's theory for calculating heat flux at the stagnation point provided a comparison to verify the effectiveness of the wrap-film technique for quantitative infrared thermography. The heat flux evaluated with the wrap-film technique resulted in excellent agreement with the theoretical solution with a mean error of 4.4%.
A wrap-film technique for infrared thermography heat-transfer measurements in high-speed wind tunnels / Running, C. L.; Rataczak, J. A.; Zaccara, M.; Cardone, G.; Juliano, T. J.. - In: EXPERIMENTAL THERMAL AND FLUID SCIENCE. - ISSN 0894-1777. - 135:(2022), p. 110604. [10.1016/j.expthermflusci.2022.110604]
A wrap-film technique for infrared thermography heat-transfer measurements in high-speed wind tunnels
Zaccara M.Penultimo
;Cardone G.Co-ultimo
;
2022
Abstract
A novel technique for obtaining quantitative infrared-thermography data on metallic (e.g., aluminum or steel) wind-tunnel models is developed. The methodology incorporates a matte-black, thin, wrap-film (3M exttrademark Wrap Film Series 1080), which is both commercially available and relatively inexpensive. Compared to painting the model to increase the surface emissivity, using a self-adhesive thin film makes it easier to obtain uniform thickness and roughness and is easier to apply and remove. The relevant surface properties (i.e., thickness, roughness, and directional emissivity) and thermal properties (i.e., thermal conductivity, specific heat capacity, and thermal diffusivity) of the wrap film have been measured and are reported. The high emissivity (0.95) and low thermal conductivity (0.23 W/(m K)) make it an excellent candidate for quantitative infrared-thermography. Using the experimentally measured properties, and the reported data-reduction techniques, stagnation-point heat flux was successfully measured on a blunt 7∘ half-angle circular cone in nominally Mach-6 flow. Fay & Riddell's theory for calculating heat flux at the stagnation point provided a comparison to verify the effectiveness of the wrap-film technique for quantitative infrared thermography. The heat flux evaluated with the wrap-film technique resulted in excellent agreement with the theoretical solution with a mean error of 4.4%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
