lnvestigation of a Pressure-Sensitive Paint Techniquefor ETW

An investigation by means of the Pressure-Sensitive Paint {PSP) technique for the use in the European Transonic Windtunnel (ETW) is reported in this paper. The so called two-gate lifetime-based PSP method is used for cryogenic application, especially to avoid the problems caused by model deformation between the wind-on and the reference conditions. In the first part of this paper, preliminary PSP tests performed in the Pilot-ETW {PETW) are introduced. New camera and LED settings and an automated PSP data acquisition system were evaluated at test conditions in the temperature range from 120 -290 Kat M = 0.78 and at a total pressure of 160 kPa. The obtained PSP results successfully visualize the pressure distribution on the profile and the quantitative agreement with conventional pressure tap data is good. In the second part, development and improvement of the PSP coating for the use at cryogenic conditions is reported. The newly developed paint has a thickness of less than 3 µm with a surface roughness R0 better than 0.2 µm. This paint has also the advantage of negligible temperature sensitivity in cryogenic condition.