INSTITUTE OF PHYSICS PUBLISHING MEASUREMENT SCIENCE AND TECHNOLOGY Meas. Sci. Technol. 13 (2002) 1552–1557 PII: S0957-0233(02)37510-6 Temperature-corrected pressure-sensitive paint measurements using a single camera and a dual-lifetime approach Jan Hradil, Claire Davis, Karen Mongey, Colette McDonagh and Brian D MacCraith 1 Optical Sensors Laboratory, School of Physical Sciences, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Republic of Ireland E-mail: brian.maccraith@dcu.ie Received 29 May 2001, accepted for publication 1 August 2002 Published 4 September 2002 Online at stacks.iop.org/MST/13/1552 Abstract The temperature dependence of luminescent coatings which measure surface pressure is a well established problem. Temperature correction of the surface pressure measurement is often carried out by incorporating a second luminescent coating or by co-immobilizing a second luminophore to provide a surface temperature profile. This usually complicates the measurement process by requiring a second camera or sophisticated filtering to distinguish between the two luminescent processes. Here, a single-camera, temperature-corrected PSP (pressure-sensitive paint) system was developed. A new oxygen-permeable sol–gel-based paint, containing both a temperature- and a pressure-sensitive luminophore is described. The fluorescence decay times of the two luminophores are separated by several orders of magnitude. This allows pressure- and temperature-dependent luminescent decay measurements to be separated in the time domain. In addition, the two luminophores were selected such that their absorption and emission spectra occur in similar spectral regions. This avoids the need for different excitation sources or detection filters. Hence a single camera with a gated image intensifier can be used to measure the lifetime of each luminophore within the same cycle. Image alignment issues experienced in dual-camera systems are also avoided. This new PSP has the potential to provide a temperature-corrected surface pressure profile using a single excitation source and detection system. Keywords: air pressure, temperature correction, pressure-sensitive paint, luminescence decay time, CCD camera, aerodynamics (Some figures in this article are in colour only in the electronic version) 1. Introduction Wind tunnel pressure measurements for aerodynamic testing are usually carried out by applying a series of individual pressure taps or transducers across the surface of a model in 1 Author to whom any correspondence should be addressed. the wind tunnel. As the number of taps which can be applied is limited, these discrete pressure readings result in an incomplete pressure map. As well as it being an expensive process, there are practical limitations in using pressure taps and transducers around thin edges and sharp corners, which tend to be the areas of most interest. 0957-0233/02/101552+06$30.00 © 2002 IOP Publishing Ltd Printed in the UK 1552