Dynamic characteristics of composite tilting pad journal bearing for turbine/generator applications

Tilting pad journal bearings have been employed for turbine, compressor, pump, and generator applications owing to their high loading capacity, excellent stability, and service durability at high operation speed compared to conventional journal bearings. For high-speed and high-performance applications, tilting pad journal bearings should reduce the rotor vibration. Therefore, the bearings are designed to have excellent damping characteristics. In this study, composite tilting pad journal bearings consisting of carbon fiber/epoxy composites and a backup metal are fabricated to increase the dynamic performance and durability. A modal analysis is performed to investigate dynamic stability of the composite tilting pad. Moreover, the damping coefficient of fluid film, oil film pressure, and orbit of rotor are calculated with respect to the liner materials under a hydrodynamic lubrication state. To verify the analysis results, hydrodynamic lubrication tests of composite and white metal tilting pad journal bearings are conducted using an industrial test bench. As a result, the composite tilting pad journal bearing has effectively reduced the rotor vibration and increased the stability and durability of the bearing system compared to the white metal tilting pad journal bearing.