Comparison of an Acoustically Optimized and an Aerodynamically Optimized Exit Guide Vane

Authors

T. Selic - Institute for Thermal Turbomachinery and Machine Dynamics, Graz Universtity of Technology, Austria
A. Marn - Institute for Thermal Turbomachinery and Machine Dynamics, Graz Universtity of Technology, Austria
F. Schönleitner - Institute for Thermal Turbomachinery and Machine Dynamics, Graz Universtity of Technology, Austria
M. Hoeger - MTU Aero Engines AG, Germany
F. Heitmeir - Institute for Thermal Turbomachinery and Machine Dynamics, Graz Universtity of Technology, Austria

Abstract

Within previous EU projects, possible modifications to the engine architecture have been investigated, that would allow for an optimized aerodynamic or acoustic design of the exit guide vanes (EGV) of the turbine exit casing (TEC). However, the engine weight should not be increased and the aerodynamic performance must be at least the same. In addition, the effect onto the aeroacoustic field downstream of the EGV needs to be considered. This paper compares two different EGV designs. The first design is an acoustically optimized EGV whereas the second EGV is optimized strictly for aerodynamics. The comparison of the two different EGV configurations is done for an operating condition similar to the engine operation point approach. The 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, the low pressure turbine (LPT) stage, and the EGVs have been designed by MTU Aero Engines. The flow field of the two different designs is being compared, and the difference in aerodynamical losses is show using 5-Hole probes as well as static surface pressure tabs and oil flow visualisation. In addition, aeroacoustic investigations were performed using an array of 24 wall-flush mounted microphones was used to acquire the sound field in the exhaust duct.