The Impact of Convective Fluid Inertia Forces on Operation of Tilting-Pad Journal Bearings

Hagemann, Thomas; Zeh, Christopher; Prölß, Maximilian; Schwarze, Hubert

doi:10.1155/2017/5683763

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…Local deformation of the sliding surface The maximum temperatures at the sensor positions in Figure 8 tend to deflect with increasing loads while they match very well for lower ones. Further validations of the code for steady-state operating conditions in the hydrodynamic lubrication regime including comparisons of local pressures, film thickness, and temperatures for different types of journal bearings can be found in [19][20][21]30,31].…”

Section: Validation For Operation In Hydrodynamic Lubrication Regimementioning

confidence: 99%

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

et al. 2018

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This paper focuses on the operating behavior of journal bearings for industrial machinery application during run-ups. For this purpose, a numerical simulation code that is based on a two-dimensional extended and generalized Reynolds equation and a full three-dimensional energy equation, was advanced by a theoretical model considering the effects of mixed friction and warming of journal components during start-up. The mixed friction routine contained the elastic half-spaces model proposed by Boussinesq, which considers the influence of rough surfaces by implementing flow factors and calculates additional stiffness and dissipation in areas with solid interactions. Furthermore, a transient term was added in the energy equation to consider the thermal inertia of journal, and bearing to ensure a realistic heating during run-ups. Results of the prediction were compared to experimental data taken from a special test rig built up for validation procedures. Besides the conventional sensors for temperature, oil flow, and relative motion between shaft and stator, a contact voltage measurement was installed to determine the intensity of mixed friction. The evaluation of experimental data by Stribeck curves, based on a shaft torsion measurement, indicated a significant influence of run-up time on frictional moment. The friction coefficient of the rotor bearing system was strongly influenced by the run-up time. A short run-up time reduced the frictional coefficient in the mixed lubrication regime while the opposite behavior was observed in the hydrodynamic lubrication regime. The numerical code predicted these tendencies in good agreement with experimental data, however, only if the transient energy model was applied.

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Section: Validation For Operation In Hydrodynamic Lubrication Regimementioning

confidence: 99%

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

et al. 2018

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“…The energy equation was added to the 2D Reynolds equation, removing the isothermal assumption, and without considering deformation, in [39,43,[50][51][52][53]. In his pioneering work, Ettles [54] considered a 1D energy equation and a 1D elasticity equation.…”

Section: Studies Based On Generalized Reynolds Equationsmentioning

confidence: 99%

Turbulence Effects in Tilting Pad Journal Bearings: A Review

2022

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This paper reviews the current knowledge on turbulence effects in tilting pad journal bearings. Turbulence is becoming increasingly important in the design of hydrodynamic bearings due to the trend to increase power density in turbomachines and consequently the operating speeds of the hydrodynamic bearings. Turbulence has a series of effects on the bearing performance which may be beneficial or detrimental, depending on the operating conditions. The main turbulence models are recalled and a historical overview on the evolution of numerical simulations of turbulent flow in tilting pad journal bearings is presented. The two broad simulation strategies used are the generalized Reynolds equation and computational fluid dynamics. The main experimental works are then reviewed, and a unified comparison of these works is provided. Novel results on the critical Reynolds number in a tilting pad journal bearing are reported. Much emphasis is given on the experimental evidence for laminar-to-turbulent transition. The evidence used in the literature is reviewed and its reliability is discussed. Lastly, some future research directions are suggested.

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“…It is flexible to consider different boundary conditions, and comprehensively described in [11,13,14]. The numerical implementation is validated for different applications of hydrodynamic operation in [11][12][13][14][16][17][18]].…”

Section: Of 15mentioning

confidence: 99%

“…The original bearing is studied in Ref. [18] at hydrodynamic operation and without jacking-oil pockets as shown in Figure 3a. Figure 3a additionally illustrates the load configuration for the subsequent investigations as well as the positions of the pad temperature sensors, which are located 4.25 mm below the sliding surface in the lateral middle plane of the bearing.…”

Section: Test Bearing and Instrumentationmentioning

confidence: 99%

Measured and Predicted Operating Characteristics of a Tilting-Pad Journal Bearing with Jacking-Oil Device at Hydrostatic, Hybrid, and Hydrodynamic Operation

2018

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

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The Impact of Convective Fluid Inertia Forces on Operation of Tilting-Pad Journal Bearings

Cited by 9 publications

References 11 publications

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Turbulence Effects in Tilting Pad Journal Bearings: A Review

Measured and Predicted Operating Characteristics of a Tilting-Pad Journal Bearing with Jacking-Oil Device at Hydrostatic, Hybrid, and Hydrodynamic Operation

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