DESIGN OF A SINGLE STAGE TURBINE FOR THE QUANTIFICATION OF AERODYNAMIC DAMPING

For an experimental study of aerodynamic damping in an axial low pressure turbine, a single stage subsonic turbine blisk is designed and aerodynamically and aeromechanically assessed. The design goals. are a low aerodynamic damping, to allow a long ring down of blade vibration, and aeromechanical stable operating points. With respect to these requirements, the aeromechanical analysis is executed using a time-linearized RANS method. The results of the final design are compared with another independent implementation of this method. Further, a preliminary flutter design tool is used to predict flutter stability and to cover the full range of current design tools. The rotor blading is manufactured as a blade integrated disk to eliminate friction damping in the planned experiment on the quantification of aerodynamic damping. To complement the study and to discuss the influence of damping, an experimental modal analysis of the manufactured blisk is completed to identify the frequency response and the damping.