Abstract: To analyze the rotor to stator rub dynamics, a coupled nonlinear differential equations with time variable coefficients is set up. In the coupled differential equations, the transient heat conductin equation and thermal bow equation are combined together with the rotor dynamic equation. Rub induced force impact and thermal impact are contained in the coupled equations. The thermal bow can be obtained directly from the asymmetric temperature. The feedback from impact force to vibration and vibration back to asymmetric heating can be calculated from the coupled equations. Rub induced contact force, asymmetric temperature distribution, thermal bend and vibration characteristics are analyzed with a generator rotor model. Harmonic components are analyzed by using frequency specturm. As a result of this calculation, the process of vibration divergence and fluctuation with time are obtained. The effects of rub location and rotating speed on the rub system are studied. A rub-induced vibration occurring in a real turbine is given. Abnormal phenomenon during rub is analyzed and explained by using the model.

Key words: Rotating machinery, Rotor, Rub, Vibration