Rudolf Kellerer

Full Rotortrain Modelling Approach for Assessment of Dynamic Stresses on Rotor and Blades due to Torsional Disturbances

Torsional rotor vibrations with low frequency always exist during normal operation due to oscillating torques at the generator. For long and flexible gas turbine blades (last stage turbine and first stage compressor), the “blade-rotor” coupled system could come into resonance with the torsion excitation. In order to ensure safe operation, the accurate prediction of eigenfrequencies and dynamic stresses in the blades and rotor is required and can be achieved by modeling the full rotor train with flexible blades.A direct modeling approach is proposed which includes 3D FE blade models coupled with a rotor/generator FE model. A 1D, 2D or 3D FE mesh can be used for the rotor model. Comparisons of predicted and measured frequencies are presented.Copyright