Effect of a Reduced Oil Flow Rate on the Static and Dynamic Performance of a Tilting Pad Journal Bearing Running in Both the Flooded and Evacuated Conditions

Abstract The mechanical efficiency of rotating machinery improves as drag power losses in bearings reduce; hence, an operation mode that reduces the supplied flow brings immediate benefits. paper presents measurements static and dynamic load performance conducted with a tilting pad journal bearing configured flooded evacuated, rates from 150% to ∼25% (or lesser) nominal magnitude, proportional shaft speed. lubricant is ISO VG 46 oil at 60 °C. four pads has center pivots single orifice feeds for condition spray bar injection evacuated condition. shaft, 102 mm diameter, operates two speeds, 6 12 krpm (= 64 m/s surface speed), while applied between (LBP). specific loads equal 345, 1034, 2068 kPa. A reduction flowrate makes both operate more eccentrically. larger eccentricity, which lowest does not align direction load, hence displaying sizable attitude angle. Pad subsurface temperatures are similar configurations, although colder by few degrees Celsius. Drag derived exit show produces up ∼40% lesser loss than flowrate. direct stiffnesses, Kxx Kyy, increase little dependency on lower magnitude 20% or so lesser, bearing. Damping coefficients, Cxx ∼ Cyy, reduce decreases. In particular low rates, 35% lower, shows rather small (though highly uncertain) damping coefficients. For sufficiently speed under smallest unit (345 kPa) produced subsynchronous vibrations broad band spectrum (subsynchronous (SSV) hash). SSV hash 30% nominal, demanded very (∼15% nominal) produce hash. bearings, amplitude motions were amplitude. experimental campaign demonstrates (flooded evacuated) can safely reduced (50% significant savings without effect pads' metal could affect long-term operation.