Retrofitting A Large Steam Turbine With A Mechanically Centered Squeeze Film Damper.

LecturePg. 29-40Reviewed is the application of a squeeze film damper to a large steam turbine that addresses high vibration passing through the first critical speed. The turbine was the fifth near identical machine purchased over the course of several expansion projects at a large LNG plant. The original machine was designed in the early 1970s, and had a highly responsive first critical speed with an amplification factor in the upper teens. With a rotor this sensitive to unbalance, heavy rubs and operational difficulties were often encountered during start up and shut down transients. For the fifth machine, it was inquired how the rotor's response sensitivity could be improved without compromising rotor interchangeability with the sister units. A squeeze film damper bearing, being the only practical solution, was proposed and implemented. The design and analysis methodology used in the development of the squeeze film damper bearing is discussed. To maintain rotor interchangeability, the design covers how the damper bearing was optimized to fit the available limited envelope. The systematic analytical approach demonstrates the importance of including support stiffness effects beyond the damper bearing. Test results are presented that illustrate the accuracy of the analysis, and the reduction in synchronous rotor response at the first critical speed