Development of Temperature Sensitive Paint Formulation for Large Scale Cryogenic Wind Tunnels

Abstract

A new Temperature-Sensitive Paint (TSP) technique for boundary-layer transition detection in a production-type large cryogenic wind tunnel is present. The formulation of Ruthenium complex TSP system has been optimized in terms of luminescence intensity and robustness. The optimum dye-binder-solvent combination has been determined through systematic sample tests. A new binder has been introduced and the resulting coating was found free from cracking at cryogenic temperatures. This is contrary to the silicone-based cryogenic TSPs that are subject to micro cracks at reduced temperatures. The new TSP can meet the root-mean-square roughness requirement less than 0.15 ?m. We applied this TSP in the JAXA 0.1-m Transonic Cryogenic Wind Tunnel, and then European Transonic Windtunnel (ETW). A variety of transition patterns have been successfully visualized.