Description: This SBIR project is aimed at developing a novel thermometry technology with upconverting phosphors for temperature measurement in NASA's high-enthalpy wind tunnels. Conventional thermographic phosphors require illumination by ultraviolet (UV) light and emit light at visible wavelengths. However, UV excitation is problematic in many large-scale facilities because it demands very expensive UV-quality windows and the UV light can be absorbed and scattered by gas species and particles in the flow path. Upconversion phosphors have been previously developed in our company and the temperature-sensing effect up to around 1000ºC with excellent sensitivity was demonstrated. A major part of this Phase I efforts will be directed towards applying these thermographic phosphors to a surface coating on a model and tested in a wind tunnel environment. The objective is to develop new surface coatings that are aerodynamically smooth, very durable, require near IR excitation and enable surface temperatures in the range of 300 K to 1500 K to be measured.

Benefits: Successful development of this novel thermometry technology will allow non-contact monitoring of high temperature surfaces, which is useful in all high temperature related processes. Therefore, its non-NASA applications are also enormous. Potential applications include, but are not limited to high temperature fields in gas turbine engines, afterburner sections, internal combustion engines and boilers. They are also useful means for kilns, the steel and iron industries to monitor temperatures throughout the product making process.

The development effort of this program will directly result in the novel technique for monitoring of surface temperatures in NASA's high-enthalpy wind tunnels. This technique has potential for aerothermodynamic heating applications, scramjet combustion research, ablator recession-rate monitoring, and gas-turbine engine health monitoring.