LDV Measurements in the Endwall Region of an Annular Turbine Cascade Through an Aerodynamic Window

Abstract

Laser-Doppler velocimetry measurements through a one millimeter hole in the casing of an annular turbine cascade were performed in the endwall region downstream of the blade row. Complementary threehole pressure probe measurements were also taken downstream of the nozzle blades, as well as blade surface pressure measurements. The object of this study was to devise methods for the measurement close to an endwall and to overcome the problems associated with optical access window contamination. The eventual aim of the project was to perform laser anemometry measurements in the tip leakage region of an operating turbine of comparable size. Good comparisons with numerical predictions of the flowfield were also obtained.