Investigation of Image-based Lifetime PSP Measurements with Sinusoidal Excitation Light

Abstract

The applicability of frequency-domain fluorescence lifetime imaging (FLIM) with a newly developed CMOS camera sensor (pco.flim) to Pressure-Sensitive Paint (PSP) measurements in wind tunnel tests was investigated. Two lifetime parameters, the phase angle and demodulation index, can be used as a function of pressure in FLIM technique. First, the characteristics of FLIM-PSP technique were examined in calibration tests. The two lifetime parameters, a phase shift and a modulation index, show different sensitivity to pressure and temperature. This indicates a potential of simultaneous pressure and temperature measurement of the FLIM-PSP technique. Next, the FLIM-PSP technique is demonstrated in a transonic wind tunnel using a delta-wing model. The obtained PSP results successfully visualize the complex pressure distribution on the model surface and the quantitative agreement with conventional pressure tap data is good.