Particle-Enhanced Temperature-Sensitive Paint: Development and Validation for High-Speed Aerothermodynamic Testing

Accurate measurement of surface temperature of high-speed vehicles, such as atmospheric entry capsules and space exploration vehicles, is critical for the design of thermal-protection systems and the development of thermal-load mitigation strategies. Temperature-sensitive paint (TSP) has emerged as a piv-otal non-intrusive method for global heat flux measurement in ground-testing facilities. However, conventional TSP formulations suffer under extreme flow 1 conditions, including self-illumination by nozzle flow, rapid fluctuations in temperature and pressure, and low signal-to-noise ratios. To address these challenges, this study presents a particle-enhanced TSP (PE-TSP) incorporating calcium silicate microparticles to increase luminescence intensity, improve temperature sensitivity, and minimize pressure dependency. Development and characterization tests revealed performance gains over a standard TSP formulation: lumines-cence intensity increased by 21%, temperature sensitivity increased by 11%, and pressure dependency was reduced by twice. For validation, both PE-TSP and the standard TSP were applied in a shock tube test section to assess dynamic response to extreme flow condition. The result showed that, owing to the increased signal-to-noise ratio, PE-TSP reduced the standard deviation by up to 33%. These results confirm the applicability of PE-TSP for high-speed aerothermodynamic diagnostics.