New device and method for measuring thermal conductivity of thin-films

Area of Science:

• Aerospace Engineering
• Materials Science

Background:

• Thermal sensitive paints (TSPs) are vital for nonintrusive detection of boundary layer transition in wind tunnel research.
• Fast response characteristics are essential for TSPs due to the transient nature of flow transition.
• Low thermal conductivity is a key property for achieving the required fast response in TSPs.

Purpose of the Study:

• To design and construct a thin-film thermal conductivity meter (TFTCM) for measuring the thermal conductivity of thin TSPs.
• To validate the accuracy and reliability of the developed TFTCM.
• To characterize the thermal conductivity of a specific TSP specimen.

Main Methods:

• Development of a novel thin-film thermal conductivity meter (TFTCM).
• Measurement of thermal conductivity for standard thin-film specimens (Kapton, Teflon, Borofloat glass).
• Testing and validation of the TFTCM using known materials and a TSP specimen (TSB-B).

Main Results:

• The TFTCM demonstrated good agreement with manufacturer-quoted values for standard specimens, validating the instrument.
• Repeatable thermal conductivity measurements were achieved for the TSP specimen (TSB-B).
• The measured thermal conductivity for the TSP specimen (TSB-B, 75 microm) was k=0.41 +/- 0.02 W/m K.

Conclusions:

• The developed TFTCM is a validated and reliable instrument for measuring the thermal conductivity of thin-film thermal sensitive paints.
• Accurate thermal conductivity measurements are achievable for TSPs, supporting their application in flow transition detection.
• The study provides essential material property data for optimizing TSP performance in aerodynamic research.