Development of a pressure sensitive paint technique for low-speed flows and its application

Pressure sensitive paint (PSP) techniques have been used to measure the pressure distribution on a model surface in high-speed flows. In this study, we developed a PSP technique that can be applied to low-speed flows. Four PSP formulations, each comprised of a porphyrin (PtOEP or PtTFPP) and a polymer (Poly(TMSP) or RTV-118), were tested and the performance of each combination was evaluated. In the static calibration, the luminescence intensity of the PSP coatings was measured from 0 kPa to 11 kPa with 0.5, 1, and 2 kPa increments. Among the four PSP formulations tested, the combination of PtOEP and RTV-118 (PSP-3) showed the best performance. In this study, the low-pressure PSP technique using PSP-3 was applied to an oblique impinging subsonic jet to measure pressure field distributions on the impingement plate at various angles of the oblique jet. For comparison, the flow over the impingement plate was visualized using an oil-film method.