Development of PSP technique for Vane Film Cooling Investigations

The present paper reports on the development of dual-luminophor Pressure Sensitive Paints (PSP) technique at University of Bergamo and on its application to the measurement of adiabatic film cooling effectiveness. An in-house calibration was carried out in order to assess the influence of temperature on PSP signal. Binary PSP have been then applied on a film cooled flat plate model for validation purposes and then used to measure the adiabatic film cooling effectiveness distribution over the leading and the trailing edge region of a high loaded high pressure nozzle guide vane. In both cases, PSP results have been compared with Liquid Crystal (TLC) data. Unlike the heat-transfer based techniques (i.e. TLC), binary PSP results are not affected by conduction phenomena, allowing to comply with adiabatic condition over test duration. PSP allowed to obtain highly resolved and high quality distributions even in the near hole exit region and where compressibility effects are relevant.