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2017
Conference Paper
Titel
Use of magnetic bearings in vibration control of a steam turbine with oil-film bearings
Abstract
It is well known that many problems in the field of noise and vibration occur in rotatory systems. To control such vibrations passive as well active measures are possible. The problems of using active control measures into rotating machinery are the energy transfer towards the rotating systems and also finding suited actuator concepts to control lateral vibrations. The most well-known passive supports in rotating machinery are the radial oil-film Bearings, widely used in turbomachinery as they allows the system to sustain high loads at high speeds. The availability and the reliability of this type of bearing is very high, since there is only fluid contact between parts with relative motion, ensuring long operational lifetime. Two of the most common bearing types are the widely used fixed-geometry bearings and the more expensive tilting-pad bearings. The tilting pad bearings are used in most extreme operational conditions due to the occurrence of rotor-bearing hydrodynamic instabilities, such as subsynchronous vibrations with high amplitude (oil-whirl and oil-whip). On the other side Active Magnetic Bearings (AMB) generate forces through magnetic fields, so there is no rotor-bearing contact (and no resulting instabilities). AMBs are used in compressors, turbines, aircrafts and other high-speed/high performance machinery. They allow an active vibration control of lateral vibrations. This paper contains the simulated vibration control of a Steam Turbine during a run-up up to the operational speed, supported in tilting- and fixed-pads bearings. The lateral vibrations are controlled either passively only by means of the RFBs or actively by substituting one of the bearings by an Active Magnetic Bearing. The results of both concepts - passive and active vibration control - are compared.
Author(s)