Abstract: A torsional vibration model of elastic continuous systems is established for a turbogenerator rotor shaft system. An analysis method to solve torsional wave equation of a complex stepped shaft system is presented. The properties of torsional vibration wave in a 200 MW of turbogenerator shaft system are calculated. The calculating results of the continuous system are compared with the discrete system and experiment results. The characters of forced torsional vibration of turbogenerator shaft system due to short-circuits or faulty synchronization are investigated by means of the method.

Key words: Elastic wave of torsional vibration, Equation of elastic wave, Turbogenerator set, CFD, Gas effect, Strouhal number, Vortex street, Vortex topology, Gas-liquid two-phase flow