0
Research Papers

Dynamic Characterization of a Novel Externally Pressurized Compliantly Damped Gas-Lubricated Bearing With Hermetically Sealed Squeeze Film Damper Modules

[+] Author and Article Information
Adolfo Delgado

Mechanical Engineering Department,
Texas A&M University,
College Station, TX 77843
e-mail: adelgado@tamu.edu

Bugra Ertas

Mechanical Systems GE Global Research Center,
Niskayuna, NY 12308
e-mail: ertas@ge.com

Manuscript received July 2, 2018; final manuscript received August 13, 2018; published online October 16, 2018. Editor: Jerzy T. Sawicki.

J. Eng. Gas Turbines Power 141(2), 021028 (Oct 16, 2018) (10 pages) Paper No: GTP-18-1423; doi: 10.1115/1.4041311 History: Received July 02, 2018; Revised August 13, 2018

Ever-increasing demand for cleaner energy is driving the need for higher power density turbomachinery while reducing cost and simplifying design. Gas-lubricated bearings are representing one of the enabling technologies that can help maximize these benefits and have been successfully implemented into turbomachinery applications with rotors weights in the order few kg's. However, load capacity and damping limitations of existing gas bearing technologies prevent the development of larger size oil-free drive trains in the MW power output range. Compliantly damped hybrid gas bearings (CHGBs) were introduced as an alternative design to overcome these limitations by providing external pressurization to discrete tilting pads while retaining flexibility in the bearing support to help tolerate misalignment and rotor-pad geometry changes. Additionally, the CHGB concept addresses damping entitlement through the application of bearing support dampers such as metal mesh. An alternative CHGB design, featuring a novel hermetically seal squeeze film damper (HSFD) in the bearing support, was introduced as alternative approach to metal mesh dampers (MMDs) to further improve bearing damping. This paper details the rotordynamic characterization of a CHGB with modular HSFD for various operating conditions. Direct and cross-coupled stiffness and damping coefficients are presented for different rotor speeds up to 12,500 rpm, frequencies of excitation between 20 and 200 Hz, bearing loads between 200 and 400 lbf, and external hydrostatic pressures reaching 180 psi. Direct comparisons to experimental results for a CHGB using MMD show 3× increase in direct damping levels when using HSFD in the compliant bearing support. In addition to the experimental results, an analytical model is presented based on the implementation of the isothermal compressible Reynolds equation coupled to a flexible support possessing a pad with three degrees-of-freedom. The numerical results capture the direct stiffness and frequency dependency but underpredict the absolute values for both cases when compared to experimental data.

FIGURES IN THIS ARTICLE
<>
Copyright © 2019 by ASME
Your Session has timed out. Please sign back in to continue.

References

Lubell, D. R. , Wade, J. L. , Chauhan, N. S. , and Nourse, J. G. , 2008, “ Identification and Correction of Rotor Instability in an Oil-Free Gas Turbine,” ASME Paper No. GT2008-50305.
Agrawal, G. , 1990, “ Foil Gas Bearings for Turbomachinery,” SAE Technical Paper No. 901236.
DellaCorte, C. , and Bruckner, R. , 2010, “ Remaining Technical Challenges and Future Plans for Oil-Free Turbomachinery,” ASME J. Eng. Gas Turbines Power, 133(4), p. 042502. [CrossRef]
Swanson, E. E. , and Heshmat, H. , 2000, “ Capabilities of Large Foil Bearings,” ASME Paper No. 2000-GT-0387.
Kim, D. , and Lee, D. , 2010, “ Design of Three-Pad Hybrid Air Foil Bearing and Experimental Investigation on Static Performance at Zero Running Speed,” ASME J. Eng. Gas Turbines Power, 132(12), p. 122504. [CrossRef]
De Santiago, O. , and Solórzano, V. , 2013, “ Experiments With Scaled Foil Bearings Is a Test Compressor Rotor,” ASME Paper No. GT2013-94087.
San Andrés, L. , and Chirathadam, T. , 2012, “ A Metal Mesh Foil Bearing and a Bump-Type Foil Bearing: Comparison of Performance for Two Similar Size Gas Bearings,” ASME J. Eng. Gas Turbines Power, 134(10), p. 102501. [CrossRef]
San Andrés, L. , and Ryu, K. , 2008, “ Flexure Pivot Tilting Pad Hybrid Gas Bearings: Operation With Worn Clearances and Two Load-Pad Configurations,” ASME J. Eng. Gas Turbines Power, 130(4), p. 042506. [CrossRef]
San Andrés, L. , and Ryu, K. , 2008, “ Hybrid Gas Bearings With Controlled Supply Pressure to Eliminate Rotor Vibrations While Crossing System Critical Speeds,” ASME J. Eng. Gas Turbines Power, 130(6), p. 062505. [CrossRef]
Morosi, S. , and Santos, I. F. , 2012, “ Experimental Investigations of Active Air Bearings,” ASME Paper No. GT2012-68766.
Ertas, B. , 2009, “ Compliant Hybrid Journal Bearings Using Integral Wire Mesh Dampers,” ASME J. Eng. Gas Turbines Power, 131(2), p. 022503. [CrossRef]
Ertas, H. , 2011, “ Compliant Hybrid Gas Journal Bearing Using Integral Wire Mesh Dampers,” U.S. Patent No. 8083413 B2. https://patents.google.com/patent/US8083413
Delgado, A. , 2015, “ Experimental Identification of Dynamic Force Coefficients for a 110 MM Compliantly Damped Hybrid Gas Bearing,” ASME J. Eng. Gas Turbines Power, 137(7), p. 072502. [CrossRef]
Wang, Y. P. , and Kim, D. , 2013, “ Experimental Identification of Force Coefficients of Large Hybrid Air Foil Bearings,” ASME J. Eng. Gas Turbines Power, 136(3), p. 032503. [CrossRef]
Kim, D. , Nicholson, B. , Rosado, L. , and Givan, G. , 2017, “ Rotordynamics Performance of Hybrid Foil Bearing Under Forced Vibration Input,” ASME. J. Eng. Gas Turbines Power, 140(1), p. 012507. [CrossRef]
Heshmat, H. , and Walton, J. F. , 2016, “ Lubricant Free Foil Bearings Pave Way to Highly Efficient and Reliable Flywheel Energy Storage System,” ASME Paper No. ES2016-59350.
Agnew, J. , and Childs, D. , 2012, “ Rotordynamic Characteristics of a Flexure Pivot Pad Bearing With an Active and Locked Integral Squeeze Film Damper,” ASME Paper No. GT2012-68564.
Delgado, A. , Cantanzaro, M. , Mitanitonna, N. , and Gerbet, M. , 2011, “ Identification of Force Coefficients in a 5-pad TiltingPad Bearing With an Integral Squeeze Film Damper,” EDF/Pprime Poitiers Workshop, Poitiers, France, Oct. 6–7, pp. 1–20.
Waumans, T. , Peirs, J. , Al-Bender, F. , and Reynaerts, D. , 2011, “ Aerodynamic Journal Bearing With a Flexible, Damped Support Operating at 7.2 Million DN,” J. Micromech. Microeng., 21(10), p. 104014. [CrossRef]
Ertas, B. , and Delgado, A. , 2018, “ Hermetically Sealed Squeeze Film damper for Operation in Oil-Free Environments,” ASME. J. Eng. Gas Turbines Power (in press).
Ertas, B. , and Delgado, A. , 2018, “ Compliant Hybrid Gas Bearing Using Modular Hermetically-Sealed Squeeze Film Dampers,” ASME. J. Eng. Gas Turbines Power (in press).
Delgado, A. , and Ertas , 2017, “ Dynamic Force Coefficients of Hydrostatic Gas Films for Recessed Flat Plates: Experimental Identification and Analytical Predictions,” ASME J. Tribol., 140(6), p. 061703.
Delgado, A. L. , San Andrés, J. , and Justak , 2004, “ Analysis of Performance and Rotordynamic Force Coefficients of Brush Seals With Reverse Rotation Ability,” ASME Paper No. GT2004-53614.
San Andres, L. , 1996, “ Turbulent Flow, Flexure-Pivot Hybrid Bearings for Cryogenic Applications,” ASME. J. Tribol., 118(1), pp. 190–200. [CrossRef]
San Andrés, L. , 1995, “ Turbulent Flow Foil Bearings for Cryogenic Applications,” ASME J. Tribol, 117(1), pp. 185–195. [CrossRef]
San Andrés, L. , 2010, “ Chapter 16: Analysis of Tilting Pad Bearings,” Modern Lubrication Notes, Texas A&M University, College Station, TX, accessed Jan. 5, 2018, http://rotorlab.tamu.edu/tribgroup/default.htm
PhadkeMadhav, S. , 1989, Quality Engineering Using Robust Design, PTR, Prentice Hall, Upper Saddle River, NJ.
Delgado, A. , Vannini, G. , Ertas, B. , Drexel, M. , and Naldi, L. , 2011, “ Identification and Prediction of Force Coefficients in a Five Pads and Four Pads Tilting Pad Bearing for Load on Pad and Load Between Pad Configuration,” ASME J. Eng. Gas Turbines Power, 133(9), p. 092503. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

CHGB with HSFD modules [5]

Grahic Jump Location
Fig. 2

Drawing showing coordinate system and geometric variable

Grahic Jump Location
Fig. 3

Flow chart for obtaining the bearing static equilibrium position and force coefficients

Grahic Jump Location
Fig. 4

CHGB with HSFD test bearing details [21] versus CHGB with MMD [13]

Grahic Jump Location
Fig. 5

Experimental test rig overview: (a) motor, (b) test article, (c) rotor, (d) FWD end slave bearing pedestal, (e) AFT end slave bearing pedestal, (f) electrohydraulic exciter, (g) shear neck spool coupling, (h) slave bearings, (i) hydrostatic inlet fitting, (j) FWD/AFT end Y direction proximity probes, (k) Y direction dynamic force transducer, (l) X direction dynamic force transducer, (m) Y direction test article housing acceleration, and (n) stinger

Grahic Jump Location
Fig. 6

Dynamic characterization detail: (a) motor, (b) test article, (c) rotor, (d) FWD end slave bearing pedestal, (e) AFT end slave bearing pedestal, (f) electrohydraulic exciter, (g) shear neck spool coupling, (h) slave bearings, (i) hydrostatic inlet fitting, (j) FWD/AFT end Y direction proximity probes, (k) Y direction dynamic force transducer, (l) X direction dynamic force transducer, (m) Y direction test article housing acceleration, (n) stinger, (o) FWD/AFT end X direction proximity probes, (p) pad TC's, (q) rotor, (r) bearing support parameters, and (s) gas film parameters

Grahic Jump Location
Fig. 7

Subsynchronous FWD whirl orbital excitation at 110 Hz while operating at 12.6 KRPM

Grahic Jump Location
Fig. 8

Bearing force coefficient for different supply pressures at the nominal load of 300 lbf (1335 N)

Grahic Jump Location
Fig. 9

Bearing force coefficient versus speed for different bearing loads and a constant supply pressure (180 psi – 12.4 bar)

Grahic Jump Location
Fig. 10

Bearing force coefficients versus excitation frequency (20–200 Hz) for multiple speeds (2500,7500, and 12,500 RPM), 180 psi (12.4 bar) supply pressure, and 300 lbf (1335 N) static load

Grahic Jump Location
Fig. 11

GEN-I [13] and GEN-II bearing synchronous force coefficients versus speeds (2500,7500, and12,500 RPM) for a 300 lbf (1335 N) static load

Grahic Jump Location
Fig. 12

Bearing subsynchronous force coefficients (GEN-I [13]-70 Hz and GEN-II-85 Hz) versus speeds (2500,7500, and 12,500 RPM) for a 300 lbf (1335 N) static load

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In