Analysis of Bearing Support System of a Steam Turbine

Bearing support system of a steam turbine is a complex structure. The performance of steam turbine not only depends on the rotor and stator, but also on the stability and support extended by the support system. This analysis highlights the advantage of solid modeling of complex structures. The static and dynamic responses of bearing support systems are obtained with three dimensional solid modeling approach. Usually the problems related to these systems are of sound and high vibrations. In turbo- generator setup, the main cause of vibrations is due to the fact that the geometric axis of rotation seldom coincides with the principle axis of inertia of rotating part, resulting in dynamic inaccuracies. Vibrations are caused by the lack of this concentricity are transmitted to these support systems. The first few natural frequencies are measured using Impact Hammer and Vibration Exciter methods. The results obtained with a PC based finite element analysis program are validated with the above experimental modal analysis methods.