Performance analysis of a transonic high-pressure turbine

Abstract

Efficiency is a crucial design parameter in any turbine development. This research presents a detailed investigation on the efficiency of a modern transonic high-pressure turbine. The work focuses on the study of the efficiency loss at different stage loading factors (ranging from ΔH/U² = 1.3 to 2.7) and various flow factors (V_ax/U = 0.41 to 0.90). In particular, the present research is of utmost importance to understand the effect of the vane trailing edge shocks in the turbine stage efficiency. The experimental work was carried out in a compression tube facility that allows testing of the turbine at temperature ratios, Re and Mach numbers, encountered in real engines. The efficiency is measured by the mechanical method. Experiments were performed with two different vanes (cooled and uncooled) at two stagger angles, four rotational speeds (4570–6500 r/min) and three pressure ratios (p₀₁/P_s3 ranging from 2.42 to 5.12). The effect of the change of reaction and rotor incidence is correlated with the performance. Three-dimensional Navier-Stokes calculations aid the interpretation of the results.