Turbine Clashing Transient Analysis: Impact of Rotor Disk Stage Onto Static Vane Stage After Shaft Rupture

Turbine shaft rupture is one of the most critical failures of aircraft engines. When rupture happens turbine work is no more equilibrated by compressor. By consequence the turbine rotor increases its angular velocity and moves axially downstream, leading to an impact between rotor and static parts. This impact may be used to limit angular velocity below the maximum admitted burst speed. On the other hand, the impact phenomena must be controlled in order to avoid that turbine components break into many damaging uncontrolled fragments. In this paper a complete transient analysis has been developed to evaluate the motion laws during these clashing phenomena. The impact dissipation coefficient, used into the motion laws, has been estimated by a non linear finite element analysis. An example of application of this methodology is also reported.