Improvement of Pressure-sensitive-paint Measurement of Rotating blades by Adjusting Oxygen Concentration under Low-pressure Conditions

Distributions of the pressure on rotating blades under low-pressure conditions were visualized by pressure-sensitive paint (PSP) at several different oxygen mole fractions. Simultaneous measurements were conducted using the main PSP, which has high-pressure sensitivity and low-temperature sensitivity, and the sub-PSP, which has low-pressure sensitivity and high-temperature sensitivity at low pressure, and pressure and temperature were determined simultaneously. However, the obtained pressure distribution was not significantly improved on the high oxygen mole fraction side even after temperature correction due to the increased pressure sensitivity of the sub-PSP. On the other hand, the ratio-of-ratio (RoR) distribution of the main PSP was emphasized by increasing the ambient oxygen mole fraction, and the low RoR regions that are considered due to the LEV and the root vortex were visualized more clearly.