Measured Performance of Tilting-Pad Journal Bearings over a Range of Preloads—Part II: Dynamic Operating Conditions

Wygant, Karl; Flack, Ronald D.; Barrett, Lloyd

doi:10.1080/05698190490504208

Cited by 18 publications

(14 citation statements)

References 6 publications

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“…Studies have also been performed when the shaft does not have a stationary eccentricity. San Andrés and De Santiago [10] studied bearing properties for plain radial bearings at high dynamic radial loading, and Wygant et al [11] determined bearing parameters as a function of preload for tilting pad bearings at dynamic loading. Other universities and institutes have also analysed bearing behaviour in test rigs.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Nässelqvist

Gustavsson

Aidanpää

2014

International Journal of Rotating Machinery

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In vertically oriented machines with journal bearing, there are no predefined static radial loads, such as dead weight for horizontal rotor. Most of the commercial software is designed to calculate rotordynamic and bearing properties based on machines with a horizontally oriented rotor; that is, the bearing properties are calculated at a static eccentricity. For tilting-pad bearings, there are no existing analytical expressions for bearing parameters and the bearing parameters are dependent on eccentricity and load angle. The objective of this paper is to present a simplified method to perform numerical simulations on vertical rotors including bearing parameters. Instead of recalculating the bearing parameters in each time step polynomials are used to represent the bearing parameters for present eccentricities and load angles. Numerical results are compared with results from tests performed in a test rig. The test rig consists of two guide bearings and a midspan rotor. The guide bearings are 4-pad tilting-pad bearings. Shaft displacement and strains in the bearing bracket are measured to determine the test rig's properties. The comparison between measurements and simulated results shows small deviations in absolute displacement and load levels, which can be expected due to difficulties in calculating exact bearing parameters.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Nässelqvist

Gustavsson

Aidanpää

2014

International Journal of Rotating Machinery

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“…The five-pad tilting pad tests have included the effect of pad pivot friction [63] and varying preload [64] on identified bearing coefficients.…”

Section: Sinusoidal Excitation With Comprehensivementioning

confidence: 99%

“…The uncertainty analysis was based on subsequent bearing identification experiments, including 2-axial groove bearings [57,58]; other studies of the 3-lobe bearing include testing of the linearity assumption the effect of load orientation on coefficients [59,60], three independent shaft orbits and the orbits resulting in the lowest uncertainty were used to identify bearing coefficients for a 3-lobe journal bearing with 0.75 preload [61,62] and five-pad tilting pad bearings [63][64][65][66]. The five-pad tilting pad tests have included the effect of pad pivot friction [63] and varying preload [64] on identified bearing coefficients.…”

Section: Sinusoidal Excitation With Comprehensivementioning

confidence: 99%

A Review on Application of Dynamic Parameters of Journal Bearing for Vibration and Condition Monitoring

Babu

Raj²,

Lakshmanan

2015

J. mech.

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The journal bearings are used to support high-speed rotors in turbo machinery which often operate above the rotor first bending critical speed. This bearing provide both lateral support and dynamic coefficients: Stiffness, damping, and mass terms, related to machine vibrations. The various methods of identifying journal bearing dynamic characteristics, from measured data, obtained from different measurement systems, are reviewed. The various approaches to the bearing identification problem are discussed. The various data processing methods in the time and frequency domains are presented. Also, vibration and condition monitoring techniques are presented. In this review, the relative strengths and weaknesses of bearing are presented and developments and trends in improving bearing measurements are documented. Future trends of journal bearing are discussed.

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“…Wygant experimentally studied tilting the pad journal bearing with ball-socket and rockerback style pivots, and found that the friction between pivot and socket will increase the attitude angle, meanwhile increase the cross coupled stiffness [12,13]. Later, he found that the preload had a relative small influence on gas film thickness, eccentricity and attitude angle of the bearing, as well as on the dynamic coefficients indicating high stability [14,15]. Fu expressed the fluid film thickness on a pad as a linear combination of the journal centre coordinates and the tilting angle of the pad [16].…”

Section: Introductionmentioning

confidence: 96%

Numerical study on tilting pad journal gas bearing with variable stiffness springs

et al. 2015

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Tilting pad journal gas bearing (TPJGB) with variable stiffness springs has been studied numerically. Elastic shims and displacement restriction component are introduced to realize the function of the variable stiffness springs. With different loads, the compliant component can be modeled as a cantilever beam or a combination of simply supported beam with moment at fixed end. This numerical solution couples the hydrodynamic fluid lubrication Reynolds equation with the deflections of the shims iteratively. The bearing performance with variable stiffness compliant shims has been studied with different bearing numbers. With variable stiffness compliant components, the bearing can provide mild stiffness under light load and higher stiffness under heavier load; the rotor and pad can move coherently. Therefore, the new structure possesses a wider operation range, namely high adaptability.

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Measured Performance of Tilting-Pad Journal Bearings over a Range of Preloads—Part II: Dynamic Operating Conditions

Cited by 18 publications

References 6 publications

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

A Review on Application of Dynamic Parameters of Journal Bearing for Vibration and Condition Monitoring

Numerical study on tilting pad journal gas bearing with variable stiffness springs

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