59886 - Development of a Lifetime Pressure Sensitive Paint Procedure for High-Pressure Vane Testing 

Optical measurements based on fast response Pressure Sensitive Paint (PSP) provide enhanced spatial resolution of the pressure field. This paper presents time-resolved luminescent lifetime PSP at 20 kHz, with precise calibrations, and results from a demonstration in an annular test section. Tests were performed at engine representative conditions in the Purdue Big Rig for Annular Stationary Turbine Analysis (BRASTA) module at the Purdue Experimental Turbine Aerothermal Lab (PETAL). This annular module is designed with access for advanced optical diagnostics. First, the laser lifetime PSP methodology is evaluated in a low technology readiness level (TRL) linear test section. A data reduction procedure using different strategies is proposed for the lifetime PSP calibration, and an optimal binning is selected from an assessment of different bin sizes to reduce the uncertainty. The overall measurement uncertainty and mapping of images to the test geometry are presented. In the annular test section, laser lifetime PSP is applied to the suction side (SS) aft portion of a high-pressure turbine vane. A 10x10 binning is applied to the PSP calibration and the surface pressure results are compared with pneumatic pressure tappings at the same location on an adjacent vane. The variation in PSP thickness is measured as a contribution to the uncertainty.  From the unsteady PSP data, the discrete Fourier transform (DFT) of time-resolved pressure is calculated during no-flow and flow conditions.