Results of Rig Test and Numerical Modeling of Rotor Oscillation with Rubbing in Water-Lubricated Bearings.

The design of water-lubricated journal bearings and the results of bench tests of a turbine generator rotor that ended in bearing damage are described. A program module has been developed for mathematical modeling of rotor oscillation with rubbing against the bearing. This process was modeled for different values of the flexibility and damping in the supports and of the sliding friction coefficient at rubbing points. Considerable attention was given to the potential risk of an accident developing into a catastrophic failure, determined by the development of asynchronous rolling of rotor over the stator elements (stator). The risk of rotor rubbing against the stator is the development of the forces of contact interaction of the rotor with the stator causing the self-excited vibrations of the rotor–supports system. The nature of these forces is related to the appearance of sliding friction at the rotating rotor-to-stator contact point. The contact interaction forces caused by the rotor-stator rubbing are governing ones as compared to other vibration excitation forces. A short time interval for development of the asynchronous rolling determines its explosive nature. It has been demonstrated that an increase in flexibility and damping of the supports does not facilitate the development of a pattern of the rotor contact interaction with a bearing—asynchronous rolling, which is dangerous to the construction integrity. With flexible supports and energy losses in the dampers, the vibrations with rubbing give rise to synchronous rolling generation with pressure forces acting on the bearings, which will not be dangerous to the construction until the machinery protection system operates in response to excessive peak-to-peak vibrations. ADP-2400 shock absorbers, whose dynamic impact properties had been determined in a shock-testing machine, were selected as dampers for the supports. With more rigid bearings and no damping, the rubbing induces the asynchronous rotor rolling over the bearing with pressure forces acting on the bearings that are dangerous for their integrity. [ABSTRACT FROM AUTHOR]