Application of the direct PSP-lifetime method on pyren-based paintas a completion of the existing DLR PSP system

摘要

Pressure Sensitive Paint (PSP) provides a pressure map on thewhole surface of a wind tunnel model without transducers and tubing. Inprinciple there are two different ways to gather experimental data-byusing the fluorescent decay time of excited luminophore molecules(lifetime method) or by detecting its integrated fluorescent emission(intensity method). During the last five years PSP measurementsutilizing the intensity of the luminescence are performed at DLR withpyren-based paints. This paint is characterized by its low temperaturesensitivity and high quantum efficiency-due to these qualities thelifetime technique is also developed for this paint type. PSPmeasurements utilizing the lifetime of the luminescence are independentof particles in the flow (dust, oil, condensed water, etc.), change indensity, light source instabilities and light reflection and lesssensitive to the model movements because there is no need for areference image. The short luminescence decay time of pyren, of theorder of 50 ns, gives the possibility to investigate fast flow processes(pressure measurements on helicopter blades, propellers, turbines, etc.)