Aerodynamic Performance of a Transonic Turbine Cascade at Off-Design Conditions

Abstract

The paper presents detailed measurements of the midspan aerodynamic performance of a transonic turbine cascade at off-design conditions. The measurements were conducted for exit Mach numbers ranging from 0.5 to 1.2 and for Reynolds numbers from 4×105 to 106. The profile losses were measured for incidence values of +14.5°, +10°, +4.5°, 0°, and −10° relative to design. To aid in understanding the loss behaviour and to provide other insights into the flow physics, measurements of blade loading, exit flow angles, trailing-edge base pressures, and the Axial Velocity Density Ratio (AVDR) were also made. It was found that the profile losses at transonic Mach numbers can be closely related to the base pressure behaviour. The losses were also affected by the AVDR.