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.

References

References
1.
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
.
2.
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
.
3.
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
.
4.
Morton
,
P. G.
,
1975
, “
Some Aspects of Thermal Instability in Generators
,” G.E.C. Internal Report No. S/W40 u183.
5.
Hesseborn
,
B.
,
1978
, “
Measurements of Temperature Unsymmetries in Bearing Journal Due to Vibration
,” Internal Report ABB Stal.
6.
Dimarogonas
,
A.
,
1974
, “
A Study of the Newkirk Effect in Turbomachinery
,”
Wear
,
28
(
3
), pp.
369
382
.
7.
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
.
8.
Newkirk
,
B.
,
1927
, “
Shaft Rubbing
,”
J. Am. Soc. Nav. Eng.
,
39
(
1
), pp.
114
120
.
9.
Schmied
,
J.
,
1987
, “
Spiral Vibrations of Rotors
,” Rotating Machinery Dynamics, Vol. 2, ASME, New York.
10.
de Jongh
,
F.
,
2008
, “
The Synchronous Rotor Instability Phenomenon—Morton Effect
,”
37th Turbomachinery Symposium
, Houston, TX, Sept. 8–11, pp.
159
167
.
11.
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.
12.
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
.
13.
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.
14.
Marscher
,
W.
, and
Illis
,
B.
,
2007
, “
Journal Bearing Morton Effect Cause of Cyclic Vibration in Compressors
,”
Tribol. Trans.
,
50
(
1
), pp.
104
113
.
15.
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.
16.
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
.
17.
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
.
18.
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
.
19.
Larsson
,
B.
,
1999
, “
Journal Asymmetric Heating—Part I: Nonstationary Bow
,”
ASME J. Tribol.
,
121
(
1
), pp.
157
163
.
20.
Larsson
,
B.
,
1999
, “
Journal Asymmetric Heating—Part II: Alteration of Rotor Dynamic Properties
,”
ASME J. Tribol.
,
121
(
1
), pp.
164
168
.
21.
Gomiciaga
,
R.
, and
Keogh
,
P.
,
1999
, “
Orbit Induced Journal Temperature Variation in Hydrodynamic Bearings
,”
ASME J. Tribol.
,
121
(
1
), pp.
77
84
.
22.
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
.
23.
Murphy
,
B.
, and
Lorenz
,
J.
,
2010
, “
Simplified Morton Effect Analysis for Synchronous Spiral Instability
,”
ASME J. Vib. Acoust.
,
132
(
5
), p.
051008
.
24.
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
.
25.
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
.
26.
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
.
27.
Suh
,
J.
, and
Palazzolo
,
A.
,
2014
, “
Three-Dimensional Thermohydrodynamic Morton Effect Simulation—Part I: Theoretical Model
,”
ASME J. Tribol.
,
136
(
3
), p.
031706
.
28.
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
.
29.
Tong
,
X.
,
Palazzolo
,
A.
, and
Suh
,
J.
,
2016
, “
Rotordynamic Morton Effect Simulation With Transient, Thermal Shaft Bow
,”
ASME J. Tribol.
,
138
(
3
), p.
031705
.
30.
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
.
31.
Berot
,
F.
, and
Dourlens
,
H.
,
1999
, “
On Instability of Overhung Centrifugal Compressors
,”
ASME
Paper No. 99-GT-202.
32.
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.
33.
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
.
34.
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.
35.
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.
36.
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.
37.
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
.
38.
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
.
39.
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
.
40.
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
.
41.
Tong
,
X.
, and
Palazzolo
,
A.
,
2016
, “
The Influence of Hydrodynamic Bearing Configuration on Morton Effect
,”
ASME
Paper No. GT2016-56654.
42.
Suh
,
J.
, and
Palazzolo
,
A.
,
2014
, “
Three-Dimensional Thermohydrodynamic Morton Effect Analysis—Part II: Parametric Studies
,”
ASME J. Tribol.
,
136
(
3
), p.
031707
.
43.
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
.
44.
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
.
45.
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.
46.
Kirk
,
G.
, and
Guo
,
Z.
,
2013
, “
Design Tool for Prediction of Thermal Synchronous Instability
,”
ASME
Paper No. DETC2013-12966.
47.
Khonsari
,
M.
, and
Beaman
,
J.
,
1986
, “
Thermohydrodynamic Analysis of Laminar Incompressible Journal Bearings
,”
ASLE Trans.
,
29
(
2
), pp.
141
150
.
48.
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
.
49.
Knight
,
J.
, and
Barrett
,
L.
,
1988
, “
Analysis of Tilting Pad Journal Bearings With Heat Transfer Effects
,”
ASME J. Tribol.
,
110
(
1
), pp.
128
133
.
50.
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
.
51.
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
.
52.
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.
53.
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
.
54.
Rouch
,
K.
,
1983
, “
Dynamics of Pivoted-Pad Journal Bearings, Including Pad Translation and Rotation Effects
,”
ASLE Trans.
,
26
(
1
), pp.
102
109
.
55.
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
.
56.
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
.
57.
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
.
58.
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
.
59.
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
.
60.
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
.
61.
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.
62.
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
.
63.
API
,
2002
, “
Axial and Centrifugal Compressors and Expander-Compressors for Petroleum, Chemical and Gas Industry Services
,” American Petroleum Institute, Washington, DC, Standard No.
617
.
64.
Marin
,
M.
,
2012
, “
Rotor Dynamics of Overhung Rotors: Hysteretic Dynamic Behavior
,”
ASME
Paper No. GT2012-68285.
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