Abstract: A Dynamic model of single-span double-disc rotor-bearing system is established, which is based on the real structure of the first span, I.e. the high and middle pressure rotor, of a 300 thousand kilowatt turbo generator rig, considering the nonlinear oil-film force model under short bearing assumption. Dynamical behaviors are analyzed under the condition of unbalance and oil-film whip. The steady state responses and bifurcations are obtained with numeral method. The nonlinear oil-film stiffness characteristics are also discussed. These results are coincided with finished experiments. The references to is provided dynamic design and fault diagnosis of rotor-bearing system.

Key words: Nonlinear oil-film force, Oil-film whip, Rotor-bearing system, Unbalance