Temperature Sensitive Paint (TSP)

Temperature sensitive paint (TSP) is, along with its pressure sensitive paint (PSP) counterpart, a coating composed of a polymer and a luminescent dye. By exploiting the luminescence quenching mechanisms, which implies that the emission light of an excited luminescent molecule can be surpressed at high temperatures or in the presence of oxygen, the surface pressure or temperature can be non-instrusively acquired on complex geometries. The oxygen permeability of a polymer is often the deciding factor of whether a coating can function as TSP or PSP. In most cases, the dye is excited either by ultraviolet or blue light sources and emits red light, which is captured by cameras outfitted with filters.

Compared infrared thermography, the TSP can be applied in water flows, at lower costs and on a wide spectrum of material surfaces. Recent advances in luminescent dye emmisivity, have made the time resolved surface temperature acquisition possible with frame rates reaching up to 4 kHz but have also increased the signal-noise ratio enough to allow the use of the single-shot lifetime method, thus compensating for the lack of flexibility the method was formerly known for.