베어링-지지구조물의 영향에 따른 터빈의 동특성 변화

A Study on the Dynamic Characteristics of Turbine due to the Stiffness of Bearing-Pedestal

It is impossible to predict accurately the dynamic behavior of turbine-generator system because bearing, and rotor characteristics are nonlinear and different from temperature, load, operation speed and bearing lubricant oil property. Especially, the characteristics of turbine hoods affect much the entire vibration characteristics of turbine. As the dynamic stiffness of turbine hoods are changed, the critical speeds of rotor are shifted. In this paper, the vibration behavior of turbine-generator is analyzed by using component mode synthesis and the critical speeds measured during shut-down are compared with the analytic results. It is confirmed that the 1st natural frequency and the mode shape are well in agreement with actual measured data.