Highly Loaded Low-Pressure Turbine: Design, Numerical, and Experimental Analysis

The performance and detailed flow physics of a highly loaded, transonic low-pressure turbine stage have been investigated numerically and experimentally. The mean rotor Zweifel coefficient was 1.35, with dh/U-2 = 2.8 and a total pressure ratio of 1.75. The aerodynamic design was based on recent developments in boundary-layer transition modeling. Steady and unsteady numerical solutions were used to design the blade geometry as well as to predict the design and offdesign performances. Measurements were acquired in a recently developed high-speed rotating turbine facility. The nozzle-vane-only and full-stage characteristics were measured with varied mass flow, Reynolds number, and freestream turbulences. The efficiency calculated from torque at the design speed and pressure ratio of the turbine was found to be 90.6%. This compared favorably to the mean-line target value of 90.5%. This paper will describe the measurements and numerical solutions in detail for both design and offdesign conditions.