Sensitivity Analysis on the Dynamic Characteristics of a 1000 MW Turbo-Generator Rotor

Taking a 1000 MW turbo-generator rotor as an example, the sensitivities to thermal effect in temperature range of 20–570 °C, both for lateral and torsional vibration, are analyzed. In addition, for lateral vibration, the sensitivities of the critical speeds are analyzed by changing bearing stiffness. The results show that increasing bearing-support stiffness leads to natural frequencies increased gradually but not linear. The first order is much more sensitive than the others. When stiffness of bearing is large enough, the natural frequencies almost do not change. For torsional vibration, the sensitivities of natural frequencies are analyzed by changing some mechanical parameters. With changing the stiffness and inertia of the rotor, their influences to the characteristics of the torsional vibration are obtained. The frequency can be modulated by changing the sectional structure of the shafting to avoid torsional vibration resonant. The results are also shown that torsional frequency and mode shape are much more sensitive to mechanical parameter than to thermal effect.