Aeromechanical Optimization of Aeronautical Low Pressure Turbine Components

The aeronautical market is facing a continuous expansion and the competition among the main aircraft manufacturers is intensely growing. At the same time, climate changes have become a matter of serious concern for our society and stringent limitations on polluting emissions have been introduced. Therefore, great emphasis is placed on producing engines able to combine high efficiency with excellent performance and reliability. The engine's overall improvement comes from optimization of the key engine’s components from different engineering points of view; among them, Low Pressure Turbines (LPT) play a crucial role. The design process of an LPT involves many different disciplines (such as Aerodynamics, Vibration Mechanics, Aeroelasticity, etc.) and, consequently, many specifications must be taken into account. In particular, the need of decreasing the overall system mass has led to critical engineering issues and, among these, aeromechanical stabilization has become one of the top priorities. In order to contain costs and time related to the design process, it would be convenient if the main aspects and related parameters coming from different optimization perspectives were all already considered in the early phases of the design process. The thesis work here presented, carried out in collaboration with GE Avio Aero, starts from a previous aerodynamics-focused study conducted by means of the Smith Chart and the two main parameters that it introduces: the Flow Coefficient and the Stage Loading Factor. The purpose is the identification of the blade profiles that show the best performance in terms of aeromechanical stabilization and to compare them with the best results from the aerodynamic point of view. The final target is to promote a functional integration between Aerodynamics and Aeromechanics in early design phases, in order to make the design process more efficient and less time-consuming.