SURFACEPRESSUREMEASUREMENTSUSINGLUMINESCENTCOATINGS

Abstract

Key Words pressure-sensitive paints, optical measurement techniques, photogrammetry, aerodynamic loads, wind tunnel testing s Abstract An optical technique is described that is often used nowadays to measure surface pressures on wind tunnel models and flight vehicles. The technique uses luminescent coatings, which are painted on the model surface, excited by light of appropriate wavelength, and imaged with digital cameras. The intensity of the emitted light is inversely proportional to the surface pressure. Hence, the surface pressures can be measured efficiently and affordably with a high spatial resolution. The theory and chemistry of how such coatings work and the parameters that affect them are presented. The required hardware and software are described, with emphasis on the different measurement systems and procedures. The various error sources are discussed, and correction schemes that can be used to minimize them are presented. Sample results, covering a wide range of conditions and applications, are presented and discussed.

A resection method applied to infrared measurements

“…The first developments were made for IRT and TSP (Thermal Sensitive Paint) applications. However, the development of the Pressure Sensitive Paint measurement technique (PSP) [3,4] was the main motivation for developing efficient image processing softwares [5]. PSP requires extremely accurate image alignment and this is why the word resection has been introduced because it is a kind of image surgery.…”

Pressure-Sensitive Paint Measurements on the NASA Common Research Model in the NASA 11-ft Transonic Wind Tunnel

“…Luminescence lifetimes of PSPs range from 0.3 to 50 μsec 3,4 , which is much faster than most imaging systems can resolve. Accordingly, most early PSP systems used continuous excitation and measured time-averaged luminescence 5 .…”

Use of pressure-sensitive paint for diagnostics in turbomachinery flows with shocks

“…In the second one, the lifetime method, pressure is determined from the decay time of luminescence after the paint has been excited by illumination flashes (Ref. 3).…”