A discusion of spatial resolution of pressure-sensitive paint

Pressure-sensitive paint (PSP) is a useful measurement technique to non-intrusively obtain a pressure distribution on a surface. Recently, PSP has been applied to micro gas flow measurements; thus the spatial resolution of PSP measurement is very important to assess the measured pressure. However, the spatial resolution has not been discussed except by Moshasrov et al. (1997). They evaluated the spatial resolution corresponds to a pressure jump on a PSP surface with consideration of an oxygen concentration distribution in a PSP layer. In this study, we have discussed the spatial resolution by numerically solving the two-dimensional diffuse equation with pressure slope as a boundary condition on a surface of PSP. The result with pressure jump, as a limiting case of pressure slope, showed good agreement with the result reported by Moshasrov et al. (1997). Moreover, it is theoretically clarified that the pressure variation with a spatial distance of lager than 8.5 times of the thickness of PSP can be completely measured by PSP without the effect of oxygen diffusion in a PSP layer.