Development of Intentional Mistuning Technologies to be applied to Aircraft Engines Low-Pressure Turbine Rotors, aiming at reducing Aeromechanical Instability.

The trend to an increasingly globalized world, together with the continuous development of new technologies, is rapidly allowing the aviation market to grow at unprecedented rates in its whole history. The high demand coming from passengers leads to a high demand of new aircrafts, capable of improving comfort and, most importantly, cut down the environmental impact of air travel. The innovative projects the two leading manufacturers, Boeing and Airbus, are working on are perfectly inserted in the mainframe of a shifting aviation model, from hub-and-spoke to point-to-point. The future airliners require next generation engines to achieve these ambitious goals, and General Electric is investing great resources in developing new machines that feature all the great technology achievements in recent aviation history and allow a strong decrease in both fuel burn and polluting emissions. The performance improvements come from the optimization of key engine components from different engineering points of view. Low Pressure Turbines are crucial modules in the overall architecture and play a fundamental role in the overall performance. If considering the series of improvements turbine rotors are due to get, aeromechanical stabilization is among the top priorities. The need of decreasing the overall system mass leads to critical engineering issues. When dealing with the optimization of turbine blades, flutter instabilities are among the top priorities to work on. Flutter stabilization not only allows the reduction of dangerous vibration phenomena, that may lead to anticipated structural failures, but also allows a more efficient gas-flow throughout the module. The work herein presented, carried out in collaboration with Avio Aero, a GE Aviation business, deals with the concept development of aeromechanically stable turbine rotors through “Mistuning”, a technology characterized by mass alternated patterns in the blades row. Despite the mistuning technology flutter stabilizing effect is widely covered by state-of-the-art studies, the aim of this project is attempting the introduction of mistuning in aviation engines modules with the development of little-mass asymmetries within Low Pressure Turbines. The target of verifying the flutter stabilizing effects in an aircraft engine is accompanied by a look at the various issues in the product life-cycle this technology introduction may involve.