Oxygen Quenching of Luminescence of Pressure Sensitive Paint for Wind Tunnel Research

• Martin Gouterman ^[1]
  1. [1] University of Washington

     University of Washington

     Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 74, Nº 6 (June), 1997, págs. 697-702
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • A technique for measuring the lift on airfoils in wind tunnels has been developed based on oxygen quenching of luminescence. A luminophor that is quenched by oxygen is dissolved in a paint containing polymer that is oxygen permeable and a volatile solvent. The paint is sprayed to form a coating on the airfoil surface. The intensity of photo excited emission depends on the effective oxygen pressure over the surface. During airflow this is reduced and the emission gets brighter. The ratio of a CCD camera image of the emission intensity taken in still air to that taken during airflow provides a map of the pressure on the airfoil surface. This is given by the Stern-Volmer equation: Io(x,y)/I(x,y) = A + B(pxy/po) where Io(x,y) is the intensity measured at point x,y in still air at pressure po, I(x,y) is the intensity at the same point during airflow, pxy is the pressure at that point during airflow, and A and B are calibration constants. The luminophor of choice was a platinum porphyrin that is excited in the near uv and emits a phosphorescence at 650 nm. The most serious problem with the method is that the emission intensity is also temperature dependent.