Effect of Oxygen Mole Fraction on Static Properties of Pressure-Sensitive Paint

The effects of the oxygen mole fraction on the static properties of pressure-sensitive paint (PSP) were investigated. Sample coupon tests using a calibration chamber were conducted for poly(hexafluoroisopropyl methacrylate)-based PSP (PHFIPM-PSP), polymer/ceramic PSP (PC-PSP), and anodized aluminum PSP (AA-PSP). The oxygen mole fraction was set to 0.1–100%, and the ambient pressure ([Formula: see text]) was set to 0.5–140 kPa. Localized Stern–Volmer coefficient [Formula: see text] increased and then decreased with increasing oxygen mole fraction. Although [Formula: see text] depends on both ambient pressure and the oxygen mole fraction, its effect can be characterized as a function of the partial pressure of oxygen. For AA-PSP and PHFIPM-PSP, which are low-pressure- and relatively low-pressure-type PSPs, respectively, [Formula: see text] peaks at [Formula: see text] kPa. In contrast, for PC-PSP, which is an atmospheric-pressure-type PSP in the investigated range, [Formula: see text] does not have a peak. [Formula: see text] has a peak at a relatively high partial pressure of oxygen due to the oxygen permeability of the polymer used in the binder. The peak of [Formula: see text] , which is the emission intensity change with respect to normalized pressure fluctuation, appears at a lower partial pressure of oxygen than that of [Formula: see text]. This is because the intensity of PSP becomes quite low at a high partial pressure of oxygen even if [Formula: see text] is high. Hence, the optimal oxygen mole fraction depends on the type of PSP and the ambient pressure range of the experiment. This optimal value can be found on the basis of the partial pressure of oxygen.