Temperature-corrected pressure-sensitive paint measurements using a single camera and a dual-lifetime approach

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.

A review of pressure-sensitive paint for high-speed and unsteady aerodynamics

“…Various strategies have been developed for coping with the temperature sensitivity of PSP. Researchers have used dual-luminophore PSP formulations to simultaneously sense pressure and temperature, infrared cameras to measure the temperature distribution over a model, or temperature-sensitive paint on half of a symmetric model to provide both temperature and pressure distributions [65][66][67]. All of these techniques involve a determination of the temperature distribution on the model, and a subsequent accounting for the temperature field in a correction of the pressure data.…”

Composite Luminescent Material for Dual Sensing of Oxygen and Temperature

“…Once such materials are obtained, they may be used in numerous formats, including planar sensor spots, [2,3] fiber-optic systems, [4,5] and as 2D foils for use in sensing imaging. [6] They may also be used as pressure-sensitive paints (PSPs) [7,8] to image the total pressure of air (via oxygen pressure) on the surface of aircrafts and cars. [9,10] However, most sensors, regardless of whether optical or electrochemical, not only respond to the species of interest but also to temperature, whose effect therefore has to be compensated for, e.g., via a second (independent) measurement.…”

Sensor Paints

“…Research on PSPs was initially performed in the former Soviet Union at the Central Aerohydrodynamic Institute, Moscow, and later on in numerous other aerodynamic research facilities all over the world including NASA and the University of Seattle (USA), JAXA (Japan), Onera (France), and DLR (Germany). The groups of Troyanovsky, [12] Gouterman and Khalil, [13] Asai and Amao, [2,14] Engler and Klein, [15] Schanze, [16] Merienne, [17] and MacCraith [18] have made essential contributions. The state of the art has recently been reviewed.…”