Development of a new class of temperature-sensitive paints operating in the green spectrum of light for aerodynamic flow applications

Abstract

Temperature-sensitive paint (TSP) is widely used in aerodynamic measurements, such as detecting laminar to turbulent transition locations, heat transfer measurements, etc. Most conventional TSP luminophores are Ruthenium and Europium complexes, whose peak absorption wavelengths occur at UV or blue spectrum of light. A new class of TSP is developed based on eosin Y as a luminophore. Eosin Y has peak emission and absorption wavelength in the green spectrum, allowing employment of conventional (Nd-YAG) lasers and scientific cameras in aerodynamic applications. The paint achieved a temperature sensitivity of 0.9 % /K, comparable to Rhodamine B based TSP, which operates in the green spectrum. The performance of the TSP is compared with the temperature and its gradient measured using an infrared camera (serving as a reference). The capability of the TSP is tested in three configurations of increasing complexity. The paint successfully detects the laminar to turbulent transition location (third configuration), indicating its promise as an addition to the existing ones for aerodynamic applications.