Jacking-oil pockets are applied in many journals and thrust bearing applications in order\nto provide a hydrostatic oil film force that ensures a wear free run-up following a successful lift-off\nprocedure. However, all components of the jacking-oil system have to be carefully designed in\norder to limit costs and prevent significant disturbance of hydrodynamic operation after deactivation\nof lift-oil. Experimental data and predictions for a four-pad tilting-pad journal bearing in load\nbetween pivot configuration are presented. Dynamic processes of the lift-off procedure as well as\ncharacteristic parameters of stationary conditions are studied. Moreover, hydrodynamic operation\nand hybrid lubrication providing a combined hydrodynamic and hydrostatic pressure distribution are\ninvestigated for sliding speeds up to 20 m/s. Analyzes of lift-off procedure prove that characteristic\nparameters such as lift-off pressures and vertical lift displacements are considerably influenced\nby manufacturing tolerances and misalignments. The comparison of hydrodynamic and hybrid\nlubrication provides a significant increase of load carrying capacity by additional jacking-oil supply\nat the maximum journal speed. In summary, results of measurements and predictions correlate well\nfor all three investigated lubrication conditions.
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