Response time scales of anodized-aluminum pressure-sensitive paints

Abstract

The response time scales of anodized-aluminum pressure-sensitive paints (AA-PSPs) are characterized by measuring their luminescent lifetimes and response times to a step-like pressure change. The luminescent lifetime is measured by a picosecond fluorescence measurement system at atmospheric conditions. The results show that the twelve AA-PSPs tested fall into two groups according to their luminescent lifetimes; one group includes AA-PSPs with organic luminophores and the other one includes AA-PSPs with metal complex luminophores. The former possesses the lifetime on the order of one nanosecond and the latter possesses that on the order of hundred nanoseconds. The AA-PSPs are also characterized by the response time to a step change in pressure generated in a shock tube. It is observed that the 90% rise times to a step change in pressure are on the order of 10μs and range from 30μs to 50μs, which lie within the tolerance caused by the thickness uncertainty in fabricating the anodized-aluminum layer. It is also found that the luminescent lifetimes are 2–4 orders of magnitude shorter than the step response times.