Open-system pressure sensitive paint for surface pressure measurements in a cryogenic wind tunnel

Pyrene-, ruthenium-, and porphyrin-based, anodized aluminum pressure sensitive paint (AA-PSP) is developed for surface pressure measurements in a cryogenic wind tunnel. These AA-PSPs were calibrated to determine the pressure sensitivity by injecting a small amount of oxygen in the test gas. The mole fraction of oxygen was varied from 4 ppm up to 2000 ppm. The calibration tests were conducted in the 0.1 m Transonic Cryogenic Wind Tunnel (TCWT) at National Aerospace Laboratory, Japan. Luminophore choice affected the pressure sensitivity with a pyrene-based AA-PSP having the best sensitivity. These AA-PSPs were applied for surface pressure measurements on a 14% thick circular arc-bump model in the TCWT. The results of pyrene- and ruthenium-based AA-PSPs showed good agreement with pressure taps. Pressure sensitivity, signal level, and uniformity of luminescent coating affected the pressure measurements.