Identification and Prediction of Force Coefficients in a Five-Pad and Four-Pad Tilting Pad Bearing for Load-on-Pad and Load-Between-Pad Configurations

Delgado, Adolfo; Vannini, Giuseppe; Ertas, Bugra; Drexel, Michael; Naldi, Lorenzo

doi:10.1115/1.4002864

Cited by 43 publications

(18 citation statements)

References 22 publications

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“…The plots show that K yy is larger for the LOP condition than for the LBP and AA condition. On the other of all configurations show significant differences each other as with the previous research [3][4][5]. Direct dampings of three bearing configurations show similar trend one after another for predicted cases.…”

Section: Applying a [K][c]supporting

confidence: 82%

“…As a tilting pad bearing has complex geometry and flexible components, the dynamic property estimation of these kinds of bearings is generally not easy compared with those of fixed geometry ones. There have been lots of efforts to get precise dynamic coefficients of a tilting pad bearing through the rig test with respect to bearing configuration such as LOP (load on pad) or LBP (load between pad) [3][4][5]. Childs and Carter [5] used the "floating" bearing design test rig with multifrequency excitation method to investigate the frequency dependent nature of the dynamic stiffness coefficients of a five pad tilting bearing in LOP and LBP configurations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rotordynamic Analysis for Integrally Geared Air Compressor Using Measured Dynamic Coefficients of Tilting Pad Journal Bearings

Kim

Lim

et al. 2015

Proceedings of the 9th IFToMM International Conference on Rotor Dynamics

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Dynamic characteristics of a tilting pad bearing strongly depend on the direction of applying load as well as the magnitude. As the bearing load of geared compressor are determined by aerodynamic forces of impellers and mesh forces of helical gears in accordance with operating speed, dynamic coefficient of each bearing also varies with respect to rotor speed. Hence, in order to ensure rotordynamic stability of geared compressor, accurate estimations of bearing loads and corresponding dynamic characteristics of tilting pad bearings in accordance with operating speeds are highly requested. In this study, bearing dynamic test rig was developed based on floating bearing housing design, with speed range from 3000 to 32,000 rpm. In order to precisely estimate lateral critical speeds and the stability of pinion rotor of integrally geared compressor, the experimental investigation has been carried out on five pads tilting-pad journal bearings of 45 mm in diameter. Static eccentricities of the tilting pad bearings were investigated with various load directions and corresponding dynamic characteristics were also obtained. Multifrequency excitations have been used to evaluate the nature of frequency dependency of the bearing dynamic coefficients. Using experimentally identified dynamic coefficients of rocker-back type tilting pad bearing with respect to rotating speed, rotordynamic analysis of gear-driven pinion rotor was carried out and compared with shaft vibration measurement. The predicted rotor behavior showed good agreement with measured one.

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Section: Applying a [K][c]supporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Rotordynamic Analysis for Integrally Geared Air Compressor Using Measured Dynamic Coefficients of Tilting Pad Journal Bearings

Kim

Lim

et al. 2015

Proceedings of the 9th IFToMM International Conference on Rotor Dynamics

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show abstract

“…Besides the imposed excitation frequencies the FFT shows the synchronous component due to the shaft unbalance. The dynamic coefficients can be finally evaluated by using the classical methodology described for instance in [11,15]. It consists in determining the bearing impedance matrix, in the frequency domain, by multiplying the force 2 × 2 complex matrix made by two direct terms and two cross-coupled ones by the corresponding inverse displacement complex matrix.…”

Section: Identification Resultsmentioning

confidence: 99%

“…This is usually done experimentally, applying dynamic loads to the rotor or to the bearing and measuring their relative displacement [8][9][10]. Identification methods are then used for the determination of the dynamic coefficients, mainly in the frequency domain [11,12].…”

Section: Introductionmentioning

confidence: 99%

Characterization of High-Power Turbomachinery Tilting Pad Journal Bearings: First Results Obtained on a Novel Test Bench

Ciulli

Forte

Libraschi³

et al. 2018

Lubricants

Self Cite

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Tilting pad journal bearings are usually employed in turbomachines for their stable behavior at high rotational speeds. Devoted test rigs have been realized to validate the predictions of theoretical models. However, the design of new high-performance and large-size bearings needs to be supported by experimental investigations on high-performance large test rigs. The main characteristics of a recently built facility for testing large tilting pad journal bearings with diameters from 150 to 300 mm are described in this work. The test rig is versatile and can be used to test bearings of different size, configurations and to investigate the influence of many parameters, even the effect of misalignment. Sample results of the static characterization of a four-pad high-performance tilting pad journal bearing are reported evidencing some transient effects. A few sample dynamic results are also reported. The presented experimental results demonstrated the capabilities of the rig for investigating the static and the dynamic characteristics of the bearings accurately measuring slow and fast variables.

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“…Pertinent literatures report many identification methods of bearing dynamic characteristic coefficients, which can be divided into stable excitation method [7,8] and transient excitation method [9,10]. The former mainly includes compound excitation method, single-frequency twice excitation method, and multifrequency excitation method.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Dynamic Performance of Water‐Lubricated Rubber Bearings with Local Contact

Ouyang

Zhang

Jin

et al. 2018

Shock and Vibration

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Accurate dynamic characteristic coefficients of water-lubricated rubber bearings are necessary to research vibration of ship propulsion system. Due to mixed lubrication state of water-lubricated rubber bearings, normal test rig and identification method are not applicable. This paper establishes a test rig to simulate shaft misalignment and proposes an identification method for waterlubricated rubber bearings, which utilizes rotor unbalanced motion to produce self-excited force rather than artificial excitation. Dynamic performance tests under different conditions are operated. The results show that when rotational speed is less than 700 r/min, even if specific pressure is 0.05 MPa, it is difficult to form complete water film for the rubber bearing which was investigated, and contact friction and collision of the shaft and bearing are frequent. In the mixed lubrication, water film, rubber, and contact jointly determine dynamic characteristics of water-lubricated rubber bearings. The contact condition has a significant effect on the bearing stiffness, and water film friction damping has a significant effect on bearing damping. As for the particular investigated bearing, when rotational speed is in the range of 400∼700 r/min and specific pressure is in the range of 0.03∼0.07 MPa, bearing stiffness is in the range of 5.6∼10.06 N/ m and bearing damping is in the range of 1.25∼2.02 Ns/ m.

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Identification and Prediction of Force Coefficients in a Five-Pad and Four-Pad Tilting Pad Bearing for Load-on-Pad and Load-Between-Pad Configurations

Cited by 43 publications

References 22 publications

Rotordynamic Analysis for Integrally Geared Air Compressor Using Measured Dynamic Coefficients of Tilting Pad Journal Bearings

Rotordynamic Analysis for Integrally Geared Air Compressor Using Measured Dynamic Coefficients of Tilting Pad Journal Bearings

Characterization of High-Power Turbomachinery Tilting Pad Journal Bearings: First Results Obtained on a Novel Test Bench

Experimental Study on the Dynamic Performance of Water‐Lubricated Rubber Bearings with Local Contact

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