Sensitivity Analysis of Three-Gate Lifetime Pressure- and Temperature-Sensitive Paint Measurements

摘要

Pressure-sensitive paint (PSP) has established itself as an important technique for measuring pressure distributions on test articles in aerodynamic test facilities. The principle of the technique has been reviewed extensively elsewhere. In its most common form, a paint containing luminescent probe molecules is applied to a test article, which is then illuminated by short-wavelength light to produce a pressure-dependent emission signal at a longer wavelength. Measurements can be performed using continuous or pulsed illumination. In the latter case, images of the test article are captured using digital cameras that are gated with respect to the train of illumination pulses. By suitable selection of the pulse repetition frequency, pulse duration, and start and end times of the camera gates, the ratio of the signals collected during two gates becomes a function of pressure, thereby forming the basis for a pressure measurement. Among the complications of such PSP measurements is the fact that signal ratios usually depend on temperature to some degree. Variations in surface temperature thus tend to produce pressure measurement errors. Recent work on lifetime-based PSP suggests that, given a suitable paint, measurement at a third gate might be added to compensate for this unwanted temperature dependence and to perform a temperature measurement in its own right. In Sec. Ⅱ, this previous work is cast in a form that lends itself to a new analysis approach. The new approach is developed in Sec. Ⅲ to guide future work in this area and has, in fact, already been used for this purpose. In Sec. Ⅳ, the model from Sec. Ⅲ is applied to published data on current paints.