Efficient Models of Turbo Units for Evaluating Dynamic Characteristics

The problem of modeling a low-pressure cylinder of a steam turbine is considered. The complete model of medium and low-pressure cylinder bodies is the base model. Two simplified hull models with different rigidity properties were taken as alternative models. This approach makes it possible to simplify the modeling process significantly. Spectra of natural frequencies and amplitude-frequency characteristics of forced oscillations are taken as comparative criteria. The study was carried out on all three steam turbine housing models. The foundation was modeled through a system of rods. The holder and rotor were considered through the system of masses. The subject of the study is natural and forced vibrations of the cylinder bodies of a steam turbine. The object of the study is a system of the most flexible casings of a medium-power steam turbine. The problem was solved using the methods of the oscillations theory and the finite element method. The simplified models are compared with the full one. Conclusions are drawn about the possibility of using various models of steam turbine casings.