Pressure Sensitive Paint Measurements Based on the Luminescence Lifetime Method

Abstract

Pressure senitive paints can be used for absolute pressure measurements on the whole model surface. The detailed pressure distribution throughout the region surrounding a flight model or a wing could be obtained in a very inexpensive way and without a very time consuming measurement technique. The basic idea for all pressuresensitive paint applications is the phenomenon that some organic dye molecules (e.g. Pyrene and Ru) which are excited on an higher energy level can be quenched by oxygen molecules. That means pressuresensitive paints resolve the partial pressure of oxygen over the model surface wwhich is covered by these organic molecules. One has to perform a calibration to get the absoluet pressure values. The formula which describes this process is called the Stern-Volmer Relation. The Stern-Volmer Relation describes both: the non-time resolved "intensity method" and the time-resolved "lifetime method". For steady flow field conditions, the intensity method is a.