Application of Lifetime-based Pressure-Sensitive Paint Technique to Cryogenic Wind Tunnel Tests

The capability of a lifetime-based Pressure-Sensitive Paint (PSP) method for application in cryogenic wind tunnels was investigated. The relevant experiments were conducted in the Pilot-European Transonic Windtunnel (PETW). The 2D airfoil model (CAST10-II) was painted with PtTFPP/PTMSP paint and tested in a nitrogen atmosphere at 150 K. PSP and pressure tap data were acquired at Mach 0.78 at a total pressure of 160 kPa. The oxygen concentration of the flow was set to 1000 ppm by continuously supplying dry air. As a result, the lifetime-based PSP method successfully visualized the pressure distribution on the airfoil model under cryogenic conditions. The quantitative agreement of PSP and pressure tap data was obtained and the difference in both data came out to be 0.05 in the pressure coefficient Cp. The accuracy of PSP data is comparable to results achievable at ambient conditions. Therefore, it may be concluded that the lifetime-based method was successfully applied under cryogenic conditions. In addition to the lifetime-based method, the intensity-based method was also conducted as a comparison. Furthermore the applicability of the lifetimebased method to tests with model deformation was evaluated.