Comparison of the Aerodynamics of Acoustically Designed Exit Guide Vanes and a State-of-the-Art Exit Guide Vane

Within previous EU projects, possible modifications to the engine architecture have been investigated, which would allow for an optimized aerodynamic or acoustic design of the exit guide vanes (EGVs) of the turbine exit casing (TEC). However, the engine weight should not be increased and the aerodynamic performance must be at least the same. This paper compares a state-of-the art TEC (reference TEC) with typical EGVs with an acoustically optimized TEC configuration for the engine operating point approach. It is shown that a reduction in sound power level for the fundamental tone (one blade passing frequency (BPF)) for this acoustically important operating point can be achieved. It is also shown that the weight of the acoustically optimized EGVs (only bladings considered) is almost equal to the reference TEC, but a reduction in engine length can be achieved. Measurements were conducted in the subsonic test turbine facility (STTF) at the Institute for Thermal Turbomachinery and Machine Dynamics, Graz University of Technology. The inlet guide vanes (IGVs), the low pressure turbine (LPT) stage, and the EGVs have been designed by MTU Aero Engines.