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Review Article

A Review of the Rotordynamic Thermally Induced Synchronous Instability (Morton) Effect

[+] Author and Article Information
Xiaomeng Tong

Mem. ASME
Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77840
e-mail: tongxiaomeng1989@tamu.edu

Alan Palazzolo

Professor
Fellow ASME
Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77840
e-mail: a-palazzolo@tamu.edu

Junho Suh

Mem. ASME
School of Mechanical Engineering,
Pusan National University,
Busan 46241, South Korea
e-mail: junhosuh77@gmail.com

Manuscript received July 31, 2016; final manuscript received May 27, 2017; published online October 20, 2017. Editor: Harry Dankowicz.

Appl. Mech. Rev 69(6), 060801 (Oct 20, 2017) (13 pages) Paper No: AMR-16-1060; doi: 10.1115/1.4037216 History: Received July 31, 2016; Revised May 27, 2017

The Morton effect (ME) is a thermally induced instability problem that most commonly appears in rotating shafts with large overhung masses and supported by fluid-film bearings. The time-varying thermal bow, due to the asymmetric journal temperature distribution, may cause intolerable synchronous vibrations that exhibit a hysteresis behavior with respect to rotor speed. First discovered by Morton in the 1970s and theoretically analyzed by Keogh and Morton in the 1990s, the ME is still not fully understood by industry and academia experts. Traditional rotordynamic analysis generally fails to predict the potential existence of ME-induced instability in the design stage or troubleshooting process, and the induced excessive rotor vibrations cannot be effectively suppressed through conventional balancing, due to the continuous fluctuation of vibration amplitude and phase angle. In recent years, a fast growing number of case studies of ME have sparked academic interest in analyzing the causes and solutions of ME, and engineers have moved from an initial trial and error approach to more research inspired modification of the rotor and bearing. To facilitate the understanding of ME, the current review is intended to give the most comprehensive summary of ME in terms of symptoms, causes, prediction theories, and solutions. Published case studies in the past are also analyzed for ME diagnosis based on both the conventional view of critical speed, separation margin (SM), and the more recent view of the rotor thermal bow and instability speed band shifting. Although no universal solutions of ME are reported academically and industrially, recommendations to help avoid the ME are proposed based on both theoretical predictions and case studies.

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References

Fillon, M. , Bligoud, J. , and Frene, J. , 1992, “ Experimental Study of Tilting-Pad Journal Bearings-Comparison With Theoretical Thermoelastohydrodynamic Results,” ASME J. Tribol., 114(3), pp. 579–587. [CrossRef]
Monmousseau, P. , Fillon, M. , and Frene, J. , 1997, “ Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings—Comparison Between Experimental Data and Theoretical Results,” ASME J. Tribol., 119(3), pp. 401–407. [CrossRef]
Dowson, D. , Hudson, J. , Hunter, B. , and March, C. , 1966, “ Paper 3: An Experimental Investigation of the Thermal Equilibrium of Steadily Loaded Journal Bearings,” Proc. Inst. Mech. Eng., 181(2), pp. 70–80.
Morton, P. G. , 1975, “ Some Aspects of Thermal Instability in Generators,” G.E.C. Internal Report No. S/W40 u183.
Hesseborn, B. , 1978, “ Measurements of Temperature Unsymmetries in Bearing Journal Due to Vibration,” Internal Report ABB Stal.
Dimarogonas, A. , 1974, “ A Study of the Newkirk Effect in Turbomachinery,” Wear, 28(3), pp. 369–382. [CrossRef]
Kellenberger, W. , 1980, “ Spiral Vibrations Due to the Seal Rings in Turbogenerators Thermally Induced Interaction Between Rotor and Stator,” ASME J. Mech. Des., 102(1), pp. 177–184. [CrossRef]
Newkirk, B. , 1927, “ Shaft Rubbing,” J. Am. Soc. Nav. Eng., 39(1), pp. 114–120. [CrossRef]
Schmied, J. , 1987, “ Spiral Vibrations of Rotors,” Rotating Machinery Dynamics, Vol. 2, ASME, New York.
de Jongh, F. , 2008, “ The Synchronous Rotor Instability Phenomenon—Morton Effect,” 37th Turbomachinery Symposium, Houston, TX, Sept. 8–11, pp. 159–167.
Panara, D. , Panconi, S. , and Griffini, D. , 2015, “ Numerical Prediction and Experimental Validation of Rotor Thermal Instability,” 44th Turbomachinery Symposium, Houston, TX, Sept. 14–17.
de Jongh, F. , and Van Der Hoeven, P. , eds., 1998, “ Application of a Heat Barrier Sleeve to Prevent Synchronous Rotor Instability,” 27th Turbomachinery Symposium, Houston, TX, Sept. 20–24, pp. 17–26.
Corcoran, J. , Rea, H. , Cornejo, G. , and Leonhard, M. , 1997, “ Discovering, the Hard Way, How a High Performance Coupling Influenced the Critical Speeds and Bearing Loading of an Overhung Radial Compressor—A Case History,” 26th Turbomachinery Symposium, Houston, TX, Sept., pp. 67–78.
Marscher, W. , and Illis, B. , 2007, “ Journal Bearing Morton Effect Cause of Cyclic Vibration in Compressors,” Tribol. Trans., 50(1), pp. 104–113. [CrossRef]
Schmied, J. , Pozivil, J. , and Walch, J. , 2008, “ Hot Spots in Turboexpander Bearings: Case History, Stability Analysis, Measurements and Operational Experience,” ASME Paper No. GT2008-51179.
API, 2005, “ Tutorial on Rotordynamics: Lateral Critical, Unbalance Response, Stability, Train Torsional and Rotor Balancing,” 2nd ed., American Petroleum Institute, Washington, DC, Standard No. 684.
Keogh, P. , and Morton, P. , 1993, “ Journal Bearing Differential Heating Evaluation With Influence on Rotor Dynamic Behaviour,” Proc. R. Soc. London, Ser. A, 441(1913), pp. 527–548. [CrossRef]
Keogh, P. , and Morton, P. , 1994, “ The Dynamic Nature of Rotor Thermal Bending Due to Unsteady Lubricant Shearing Within a Bearing,” Proc. R. Soc. London, Ser. A, 445(1924), pp. 273–290. [CrossRef]
Larsson, B. , 1999, “ Journal Asymmetric Heating—Part I: Nonstationary Bow,” ASME J. Tribol., 121(1), pp. 157–163. [CrossRef]
Larsson, B. , 1999, “ Journal Asymmetric Heating—Part II: Alteration of Rotor Dynamic Properties,” ASME J. Tribol., 121(1), pp. 164–168. [CrossRef]
Gomiciaga, R. , and Keogh, P. , 1999, “ Orbit Induced Journal Temperature Variation in Hydrodynamic Bearings,” ASME J. Tribol., 121(1), pp. 77–84. [CrossRef]
Balbahadur, A. C. , and Kirk, R. , 2004, “ Part I—Theoretical Model for a Synchronous Thermal Instability Operating in Overhung Rotors,” Int. J. Rotating Mach., 10(6), pp. 469–475. [CrossRef]
Murphy, B. , and Lorenz, J. , 2010, “ Simplified Morton Effect Analysis for Synchronous Spiral Instability,” ASME J. Vib. Acoust., 132(5), p. 051008. [CrossRef]
Childs, D. , and Saha, R. , 2012, “ A New, Iterative, Synchronous-Response Algorithm for Analyzing the Morton Effect,” ASME J. Eng. Gas Turbines Power, 134(7), p. 072501. [CrossRef]
de Jongh, F. , and Morton, P. , 1994, “ The Synchronous Instability of a Compressor Rotor Due to Bearing Journal Differential Heating,” ASME Paper No. 94-GT-035.
Lee, J. , and Palazzolo, A. , 2012, “ Morton Effect Cyclic Vibration Amplitude Determination for Tilt Pad Bearing Supported Machinery,” ASME J. Tribol., 135(1), p. 011701. [CrossRef]
Suh, J. , and Palazzolo, A. , 2014, “ Three-Dimensional Thermohydrodynamic Morton Effect Simulation—Part I: Theoretical Model,” ASME J. Tribol., 136(3), p. 031706. [CrossRef]
Grigor’ev, B. S. , Fedorov, A. E. , and Schmied, J. , 2015, “ New Mathematical Model for the Morton Effect Based on the THD Analysis,” Nineth IFToMM International Conference on Rotor Dynamics, Milan, Italy, Sept. 22–25, pp. 2243–2253.
Tong, X. , Palazzolo, A. , and Suh, J. , 2016, “ Rotordynamic Morton Effect Simulation With Transient, Thermal Shaft Bow,” ASME J. Tribol., 138(3), p. 031705. [CrossRef]
Tong, X. , and Palazzolo, A. , 2016, “ Double Overhung Disk and Parameter Effect on Rotordynamic Synchronous Instability—Morton Effect—Part I: Theory and Modeling Approach,” ASME J. Tribol., 139(1), p. 011705. [CrossRef]
Berot, F. , and Dourlens, H. , 1999, “ On Instability of Overhung Centrifugal Compressors,” ASME Paper No. 99-GT-202.
Kocur, J. , and de Jongh, F. , 2000, “ Thermal Rotor Instability in Gas Compressors,” 14th International Gas Convention, Caracas, Venezuela, May 10–12, pp. 1–14.
Kirk, G. , Guo, Z. , and Balbahadur, A. , 2003, “ Synchronous Thermal Instability Prediction for Overhung Rotors,” 32nd Turbomachinery Symposium, Houston, TX, Sept. 8–11, pp. 121–135.
Lorenz, J. , and Murphy, B. , 2011, “ Case Study of Morton Effect Shaft Differential Heating in a Variable-Speed Rotating Electric Machine,” ASME Paper No. GT2011-45228.
Faulkner, H. , Strong, W. , and Kirk, R. , 1997, “ Thermally Induced Synchronous Instability of a Radial Inflow Overhung Turbine—Part II,” ASME Design Engineering Technical Conference, Sacramento, CA, Sept. 14–17, Paper No. DETC97/VIB-4174.
Carrick, H. B. , 1999, “ Integrally Geared Compressors and Expanders in the Process Industry,” Seventh IMechE European Congress on Fluid Machinery for the Oil, Petrochemical, and Related Industries, Hague, The Netherlands, Apr. 15–16.
Guo, Z. , and Kirk, G. , 2011, “ Morton Effect Induced Synchronous Instability in Mid-Span Rotor–Bearing Systems—Part I: Mechanism Study,” ASME J. Vib. Acoust., 133(6), p. 061004. [CrossRef]
Eckert, L. , and Schmied, J. , 2008, “ Spiral Vibration of a Turbogenerator Set: Case History, Stability Analysis, Measurements and Operational Experience,” ASME J. Eng. Gas Turbines Power, 130(1), p. 012509. [CrossRef]
Paranjpe, R. , and Han, T. , 1995, “ A Transient Thermohydrodynamic Analysis Including Mass Conserving Cavitation for Dynamically Loaded Journal Bearings,” ASME J. Tribol., 117(3), pp. 369–378. [CrossRef]
Tong, X. , and Palazzolo, A. , 2016, “ Double Overhung Disk and Parameter Effect on Rotordynamic Synchronous Instability—Morton Effect—Part II: Occurrence and Prevention,” ASME J. Tribol., 139(1), p. 011706. [CrossRef]
Tong, X. , and Palazzolo, A. , 2016, “ The Influence of Hydrodynamic Bearing Configuration on Morton Effect,” ASME Paper No. GT2016-56654.
Suh, J. , and Palazzolo, A. , 2014, “ Three-Dimensional Thermohydrodynamic Morton Effect Analysis—Part II: Parametric Studies,” ASME J. Tribol., 136(3), p. 031707. [CrossRef]
Tucker, P. , and Keogh, P. , 1996, “ On the Dynamic Thermal State in a Hydrodynamic Bearing With a Whirling Journal Using CFD Techniques,” ASME J. Tribol., 118(2), pp. 356–363. [CrossRef]
Lund, J. , and Tonnesen, J. , 1984, “ An Approximate Analysis of the Temperature Conditions in a Journal Bearing—Part II: Application,” ASME J. Tribol., 106(2), pp. 237–244. [CrossRef]
Lorenz, J. , 2009, “ Implementation of Fluid-Film Bearing Shaft Differential Heating Calculations Using Commercial CFD Software,” M.S. thesis, University of Illinois at Urbana-Champaign, Champaign, IL.
Kirk, G. , and Guo, Z. , 2013, “ Design Tool for Prediction of Thermal Synchronous Instability,” ASME Paper No. DETC2013-12966.
Khonsari, M. , and Beaman, J. , 1986, “ Thermohydrodynamic Analysis of Laminar Incompressible Journal Bearings,” ASLE Trans., 29(2), pp. 141–150. [CrossRef]
Kim, J. , Palazzolo, A. , and Gadangi, R. , 1995, “ Dynamic Characteristics of TEHD Tilt Pad Journal Bearing Simulation Including Multiple Mode Pad Flexibility Model,” ASME J. Vib. Acoust., 117(1), pp. 123–135. [CrossRef]
Knight, J. , and Barrett, L. , 1988, “ Analysis of Tilting Pad Journal Bearings With Heat Transfer Effects,” ASME J. Tribol., 110(1), pp. 128–133. [CrossRef]
Gadangi, R. , Palazzolo, A. , and Kim, J. , 1996, “ Transient Analysis of Plain and Tilt Pad Journal Bearings Including Fluid Film Temperature Effects,” ASME J. Tribol., 118(2), pp. 423–430. [CrossRef]
He, M. , Allaire, P. , Barrett, L. , and Nicholas, J. , 2005, “ Thermohydrodynamic Modeling of Leading-Edge Groove Bearings Under Starvation Condition,” Tribol. Trans., 48(3), pp. 362–369. [CrossRef]
Morton, P. , 2008, “ Unstable Shaft Vibrations Arising From Thermal Effects Due to Oil Shearing Between Stationary and Rotating Elements,” Ninth IMechE International Conference on Vibrations of Rotating Machinery, Exeter, UK, Sept., pp. 383–391.
Al-Ghasem, A. , and Childs, D. , 2006, “ Rotordynamic Coefficients Measurements Versus Predictions for a High-Speed Flexure-Pivot Tilting-Pad Bearing (Load-Between-Pad Configuration),” ASME J. Eng. Gas Turbines Power, 128(4), pp. 896–906. [CrossRef]
Rouch, K. , 1983, “ Dynamics of Pivoted-Pad Journal Bearings, Including Pad Translation and Rotation Effects,” ASLE Trans., 26(1), pp. 102–109. [CrossRef]
San Andrés, L. , and Tao, Y. , 2013, “ The Role of Pivot Stiffness on the Dynamic Force Coefficients of Tilting Pad Journal Bearings,” ASME J. Eng. Gas Turbines Power, 135(11), p. 112505. [CrossRef]
Gaines, J. , and Childs, D. , 2016, “ The Impact of Pad Flexibility on the Rotordynamic Coefficients of Tilting Pad Journal Bearings,” ASME J. Eng. Gas Turbines Power, 138(8), p. 082501. [CrossRef]
Wilkes, J. , and Childs, D. , 2012, “ Tilting Pad Journal Bearings—A Discussion on Stability Calculation, Frequency Dependence, and Pad and Pivot,” ASME J. Eng. Gas Turbines Power, 134(12), p. 122508. [CrossRef]
Lund, J. , and Pedersen, L. , 1987, “ The Influence of Pad Flexibility on the Dynamic Coefficients of a Tilting Pad Journal Bearing,” ASME J. Tribol., 109(1), pp. 65–70. [CrossRef]
Earles, L. , Palazzolo, A. , and Armentrout, R. , 1990, “ A Finite Element Approach to Pad Flexibility Effects in Tilt Pad Journal Bearings—Part I: Single Pad Analysis,” ASME J. Tribol., 112(2), pp. 169–176. [CrossRef]
Ettles, C. , 1980, “ The Analysis and Performance of Pivoted Pad Journal Bearings Considering Thermal and Elastic Effects,” J. Lubr. Technol., 102(2), pp. 182–191. [CrossRef]
Balbahadur, A. , 2001, “ A Thermoelastohydrodynamic Model of the Morton Effect Operating in Overhung Rotors Supported by Plain or Tilting Pad Journal Bearings,” Ph.D. thesis, Virginia Tech, Blacksburg, VA.
Balbahadur, A. , and Kirk, R. , 2004, “ Part II—Case Studies for a Synchronous Thermal Instability Operating in Overhung Rotors,” Int. J. Rotating Mach., 10(6), pp. 477–487. [CrossRef]
API, 2002, “ Axial and Centrifugal Compressors and Expander-Compressors for Petroleum, Chemical and Gas Industry Services,” American Petroleum Institute, Washington, DC, Standard No. 617.
Marin, M. , 2012, “ Rotor Dynamics of Overhung Rotors: Hysteretic Dynamic Behavior,” ASME Paper No. GT2012-68285.

Figures

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Fig. 1

Rotor thermal instability technical publications

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Fig. 3

Feedback diagram for ME prediction

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Fig. 4

Illustration of unbalance threshold method

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Fig. 5

Illustration of the thermal ratio method

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Fig. 6

Diagram of the staggered integration scheme

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Fig. 7

Diagram illustrating the hybrid FEM of Tong et al. [29]

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Fig. 8

Illustrations of thermal boundaries conditions of Tong and Palazzolo [30]

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Fig. 9

Phase relationship of the high and hot spot

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Fig. 10

Test rig of Tong and Palazzolo

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Fig. 11

Instability speed band by Tong and Palazzolo [40]

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