Pressure resolution of a PSP based measurement system with non-linear intensity response

Tarun Dhall, Cengiz Camci

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


An experimental study has been conducted at The Pennsylvania State University's Turbomachinery Aero-Heat Transfer Laboratory to develop an automated facility for calibration of Pressure Sensitive Paints (PSP). This paper deals with the calibration results of a particular PSP sample and their associated implications. Experimental setup of the facility and the calibration procedure have been briefly discussed. Results of this study, presented here in detail, reveal a unique character of the intensity ratio - pressure ratio relationship for the sample PSP. Rather than following the conventional linear pattern, this relationship was found to have a highly nonlinear character which was approximated with an exponential function using curve-fitting analysis. Repeated tests were conducted to confirm this observation. Such uniqueness of this relationship has a significant impact on not only the sensitivity range but also the pressure resolution capability of the paint. Since the intensity resolution of a PSP based measurement system is fixed (depending on the imaging device used), an exponential relation between intensity and pressure will lead to a variation in the corresponding pressure resolution over the whole range of pressures. In the present case, where a 10-bit CCD camera was used, such a variation was observed to be following a fourth-order polynomial function. Further, a simulated analysis for a 16-bit camera showed a significant improvement in pressure resolution for the same paint, although it still exhibited distinct variability over the complete pressure range. Finally, an error analysis was carried out over the different tests conducted as part of this study. Pressure values were estimated using the calibration equation and recorded intensity, and compared against measured values. It was observed that, in general, rms error increased as the pressure resolution of the paint decreased.

Original languageEnglish (US)
Title of host publication46th AIAA Aerospace Sciences Meeting and Exhibit
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781563479373
StatePublished - 2008

Publication series

Name46th AIAA Aerospace Sciences Meeting and Exhibit

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering


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