Minimum Weight Design of Aero Engine Turbine Disks

Abstract

The aero engine rotating parts are always fracture critical components and their failure in service affects the aircraft safety. Rotors / disks will burst at a certain speed if they operate at ever-increasing speed. Rotor burst is one of important failure mode in aero engine and resulting in disk disintegration into multiple fragments with high speed resulting in containment breach. Disks are subjected to fatigue loading and it limits the service life. Fatigue loading on disk includes high temperature environment, tremendous centrifugal and aerodynamic forces caused by blades. The main aspect of turbine disk design is to safe guard against LCF failure. Design of disk should ensure that stresses due to thermal, centrifugal and aerodynamics loads during operating conditions should be within the limits. Turbine disks are also designed to operate at speed above 20% of maximum operating speed for maximum power and referred as over speed capability or burst margin. This over speed capability may require for the aircraft during emergency conditions. The objective of this study is to design a turbine disk for minimum weight. A numerical investigation is performed to predict stresses and burst margins of turbine disk. A parametric disk model is developed with bore width, bore height, web width and web height parameters. Optimization of turbine disk design is carried out to achieve minimum weight. Sensitivity studies are carried out to understand the geometry parameters influence on the stress and burst margins.