Session: 23-10: Squeeze Film Dampers

Submission Number: 177166

Integral Squeeze Film Dampers for Large Turbogenerators 

Decarbonization and the risk of high energy costs drive the demand for ever more efficient combined cycle power plants. Designing steam turbines for maximum efficiency usually requires slender and long rotors as well as highly efficient seals. Such designs can be very demanding on rotordynamic stability and come with an increased risk of sub-synchronous vibrations due to fluid-structure interactions. 

Squeeze film dampers have been used for decades in industrial steam and gas turbines as well as compressors to improve rotordynamic stability but have seen little use so far in utility scale applications. These components allow independent tuning of stiffness and damping coefficients, enabling designs with low stiffness-to-damping ratios, providing a significant boost to the modal damping of potentially unstable rotordynamic modes. 

The low stiffness of the damper’s springs and their limited HCF resistance pose a particular challenge for heavy duty turbogenerators where significant dynamic forces due to unbalance or other types of forced excitation might cause increased synchronous vibrations and HCF failure of the springs in the worst case. 

We here report on the successful implementation of an integral squeeze film dampers in several utility steam turbines and their effectiveness in reducing sub-synchronous vibrations while maintaining good synchronous vibration behavior. This is achieved by precisely defining and controlling the damper’s stiffness and damping properties to provide a sufficient boost for the modal damping of the potentially unstable mode while maintaining sufficient dynamic stiffness and HCF resistance for synchronous response. We also report on validation testing of these properties in the workshop and independent measurements of the spring deflections and total relative shaft vibrations in the field. 

Presenting Author: Roland Georg Levin Rojas Siemens Energy

Presenting Author Biography: Dr. Roland Levin received his PhD in theoretical physics from Karlsruhe Institute of Technology in 2012. Afterwards he started working for the utility steam turbine business of Siemens Energy and advanced to his current position, focusing on rotor dynamics and fluid-film bearing technology.
Apart from providing rotor dynamics expertise to numerous projects, he has extended Siemens Energy’s utility steam turbine fluid film bearing portfolio by implementing new technologies.
He currently holds the position of Discipline Expert for rotor dynamics in steam turbine engineering.

Authors:

Roland Georg Levin Rojas Siemens Energy
David Felwor Siemens Energy Global GmbH & Co. KG
Donald Paquette Siemens Energy
Filippo Cangioli Waukesha Bearings