Experimental and computational investigation of flow through an annular turbine cascade

Abstract

The purpose of this research was to compare numerical predictions with experimental results and to devise an accurate laser anemometry technique to measure in the endwall region of a confined annulus. Flowfield characteristics were computed using a three-dimensional flow solver with the numerical plane coincident with the experimental measurement location. An annular turbine cascade, designed for laser-Doppler velocimetry, was modified to obtain blade passage midspan surface pressure measurements. A range of predicted subsonic and transonic midspan surface pressures were compared favorably with experimental measurements. Two-dimensional Mach number, flow angle, and turbulence intensity measurements were obtained with a fiber-optics laser- Doppler velocimeter. These measurements were performed through a 1.0922 millimeter opening in the endwall at depths ranging from 0.01 mm to 3.34 mm and the results were compared with numerical predictions. (AN)