Temperature Sensitive Paint is luminescent paint proving an opportunity to determine surface temperature distributions easily. TSP may be used for visualization of heat transfer rate, boundary layer transition, flow separation and flow reattachment on the models in transonic, supersonic and shock wind tunnels.

This technique is very similar to LPS except that the coating is temperature sensitive rather than pressure sensitive. The luminescence of TSP is decreases, as the temperature increases. As in LPS, a ratio of two images provides the temperature. In this case, one image is taken at a known, constant temperature, and the other is taken at the unknown conditions. The ratio of the two images is then converted to temperature using the appropriate calibration. As in LPS testing, during the acquisition of the images, the test surface is exposed to excitation light in only a narrow frequency band. The detector is then notch filtered to pass only the luminescence band for the luminescent molecule. Of course, these two bands must not overlap.

OPTROD Ltd. manufactures Temperature Sensitive Paint TSP E40 for temperature range 15?60°C. TSP is excited by the ultraviolet light of 280?390nm spectral range and emits red light of 580-630nm spectral range. Intensity of emitted light decreases at temperature increase with the rate of 45°C. TSP is destroyed at the temperature above 120°C.

TSP may be applied by a sprayer to the surfaces made of steel, aluminum, wood and some types of plastic. TSP thickness is about 5 micrometers. TSP drying time after application is about 24 hours at normal room temperature (18°<25°C) or about 2 hours at 80oC.

TSP is also available in form of adhesive tap: TSP E40T. TSP-tape is attached to the model surface like an ordinary adhesive tape. Application of TSP-tape needs few minutes. However, TSP-paint allows to cover the surface of complicated shape, while TSP-tape may be applied only to the flat surface. The thickness of TSP-tape is 80?90 micrometers. TSP- tape keeps adhesion up to 60o C.

Typical temperature dependencies of Temperature Sensitive Paints.

Emission and excitation spectra of Temperature Sensitive Paint TSP E40.