Time response of anodized aluminum pressure-sensitive paint

The response time of anodized aluminum pressure-sensitive paint (AA-PSP) was studied to develop the capability of making global pressure measurements in unsteady flow conditions. This pressure-sensitive paint (PSP) uses anodized aluminum as a porous supporting matrix, which improves the response time by increasing the oxygen diffusion process in the PSP layer. A response time of 34.8 mus was obtained from AA-PSP with 4.3-mum matrix thickness. Response times of PSPs were measured from a step change of pressure created by a normal shock wave in a shock tube. The response time of AA-PSP is dependent on the matrix thickness, with a thin supporting matrix giving a fast response time. Compared with other porous PSPs, such as thin-layer chromatography PSP, porous polymer/ceramic PSP, and conventional polymer matrix PSP, AA-PSP has the fastest response time. The material of the supporting matrix greatly changed the response time of the PSP. The increase in surface temperature of the paint caused by shock waves was also measured using a temperature-sensitive paint (rhodamine-B on anodized aluminum) to understand the temperature effect of AA-PSP.