The present work advances experimental results and analytical predictions on the dynamic performance of an integral squeeze film damper (ISFD) for application in a high-speed super-critical CO2 (sCO2) expander. The test campaign focused on conducting controlled orbital motion mechanical impedance testing aimed at extracting stiffness and damping coefficients for varying end seal clearances, excitation frequencies, and vibration amplitudes. In addition to the measurement of stiffness and damping, the testing revealed the onset of cavitation for the ISFD. Results show damping behavior that is constant with vibratory velocity for each end seal clearance case until the onset of cavitation/air ingestion, while the direct stiffness measurement was shown to be linear. Measurable added inertia coefficients were also identified. The predictive model uses an isothermal finite element method to solve for dynamic pressures for an incompressible fluid using a modified Reynolds equation accounting for fluid inertia effects. The predictions revealed good correlation for experimentally measured direct damping, but resulted in grossly overpredicted inertia coefficients when compared to experiments.
Dynamic Characterization of an Integral Squeeze Film Bearing Support Damper for a Supercritical Co2 Expander
GE Global Research Center,
Niskayuna, NY 12308
Texas A&M University,
College Station, TX 77843
Southwest Research Institute,
San Antonio, TX 78238
Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 3, 2017; final manuscript received August 8, 2017; published online November 14, 2017. Editor: David Wisler.
Ertas, B., Delgado, A., and Moore, J. (November 14, 2017). "Dynamic Characterization of an Integral Squeeze Film Bearing Support Damper for a Supercritical Co2 Expander." ASME. J. Eng. Gas Turbines Power. May 2018; 140(5): 052501. https://doi.org/10.1115/1.4038121
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