Abstract

This paper investigates the influence of misaligned journal bearing effects on the thermally induced rotor instability (Morton effect “ME”) problem. The Morton effect is caused by uneven viscous heating of the journal in a fluid film bearing, which causes thermal bending, especially in rotors with an overhung disc or coupling weight. The thermally induced bending in the shaft may cause a vibration instability, which results in an excessive level of synchronous vibration. Previous research focused on parametric studies of the rotor and bearing design parameters, including overhung mass, bearing radial clearance, and lubricant viscosity. The present study investigates the influence of journal misalignment on the Morton effect. A coupled fluid-thermal-structural, three-dimensional finite element model (FEM) is developed to simulate fluid film pressures and temperatures, and shaft temperatures and vibrations. Simulations were conducted with different ratios of journal misalignment, and different pad-pivot types to determine their effect on the phenomenon. The simulation results indicate that the amplitude of the misalignment angle affects the instability speed range (ISR) caused by the Morton effect under certain conditions.

References

References
1.
Tong
,
X.
,
Palazzolo
,
A.
, and
Suh
,
J.
,
2017
, “
A Review of the Rotordynamic Thermally Induced Synchronous Instability (Morton) Effect
,”
ASME Appl. Mech. Rev.
,
69
(
6
), p.
060801
. 10.1115/1.4037216
2.
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
.
3.
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
. 10.1098/rspa.1994.0061
4.
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
. 10.1115/1.4007884
5.
Suh
,
J.
, and
Palazzolo
,
A.
,
2015
, “
Three-Dimensional Dynamic Model of TEHD Tilting-Pad Journal Bearing–Part I: Theoretical Modeling
,”
ASME J. Tribol.
,
137
(
4
), p.
041703
. 10.1115/1.4030020
6.
Suh
,
J.
, and
Palazzolo
,
A.
,
2015
, “
Three-Dimensional Dynamic Model of TEHD Tilting-Pad Journal Bearing—Part II: Parametric Studies
,”
ASME J. Tribol.
,
137
(
4
), p.
041704
. 10.1115/1.4030021
7.
Suh
,
J.
, and
Palazzolo
,
A.
,
2014
, “
Three-Dimensional Thermohydrodynamic Morton Effect Simulation—Part I: Theoretical Model
,”
ASME J. Tribol.
,
136
(
3
), p.
031706
. 10.1115/1.4027309
8.
Suh
,
J.
, and
Palazzolo
,
A.
,
2014
, “
Three-Dimensional Thermohydrodynamic Morton Effect Analysis—Part II: Parametric Studies
,”
ASME J. Tribol.
,
136
(
3
), p.
031707
. 10.1115/1.4027310
9.
Tong
,
X.
,
Palazzolo
,
A.
, and
Suh
,
J.
,
2016
, “
Rotordynamic Morton Effect Simulation With Transient, Thermal Shaft Bow
,”
ASME J. Tribol.
,
138
(
3
), p.
031705
. 10.1115/1.4032961
10.
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
. 10.1115/1.4033888
11.
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
. 10.1115/1.4033892
12.
Tong
,
X.
, and
Palazzolo
,
A.
,
2017
, “
Measurement and Prediction of the Journal Circumferential Temperature Distribution for the Rotordynamic Morton Effect
,”
ASME J. Tribol.
,
140
(
3
), p.
031702
. 10.1115/1.4038104
13.
Tong
,
X.
, and
Palazzolo
,
A.
,
2018
, “
Tilting Pad Gas Bearing Induced Thermal Bowrotor Instability
,”
Tribol. Int.
,
121
, pp.
269
279
. 10.1016/j.triboint.2018.01.066
14.
Bouyer
,
J.
, and
Fillon
,
M.
,
2002
, “
An Experimental Analysis of Misalignment Effects on Hydrodynamic Plain Journal Bearing Performances
,”
ASME J. Tribol.
,
124
(
2
), pp.
313
319
. 10.1115/1.1402180
15.
Sun
,
J.
, and
Gui
,
C. L.
,
2004
, “
Hydrodynamic Lubrication Analysis of Journal Bearing Considering Misalignment Caused by Shaft Deformation
,”
Tribol. Int.
,
37
(
10
), pp.
841
848
. 10.1016/j.triboint.2004.05.007
16.
El-Butch
,
A. M.
, and
Ashour
,
N. M.
,
2005
, “
Transient Analysis of Misaligned Elastic Tilting Pad Journal Bearing
,”
Tribol. Int.
,
38
(
1
), pp.
41
48
. 10.1016/j.triboint.2004.05.008
17.
Sun
,
J.
,
Deng
,
M.
, Fu, Y., and Gui, C.,
2010
, “
Thermohydrodynamic Lubrication Analysis of Misaligned Plain Journal Bearing With Rough Surface
,”
ASME J. Tribol.
,
132
(
1
), p.
011704
. 10.1115/1.4000515
18.
Xu
,
G.
,
Zhou
,
J.
,
Geng
,
H.
,
Lu
,
M.
,
Yang
,
L.
, and
Yu
,
L.
,
2015
, “
Research on the Static and Dynamic Characteristics of Misaligned Journal Bearing Considering the Turbulent and Thermohydrodynamic Effects
,”
ASME J. Tribol.
,
137
(
2
), p.
024504
. 10.1115/1.4029333
19.
Suh
,
J.
, and
Choi
,
Y.
,
2016
, “
Pivot Design and Angular Misalignment Effects on Tilting Pad Journal Bearing Characteristics: Four Pads for Load on Pad Configuration
,”
Tribol. Int.
,
102
, pp.
580
599
. 10.1016/j.triboint.2016.05.049
20.
Das
,
S.
,
Guha
,
S. K.
, and
Chattopadhyay
,
A. K.
,
2002
, “
On the Steady-State Performance of Misaligned Hydrodynamic Journal Bearings Lubricated With Micropolar Fluids
,”
Tribol. Int.
,
35
(
4
), pp.
201
210
. 10.1016/S0301-679X(01)00065-2
21.
Ebrat
,
O.
,
Mourelatos
,
Z. P.
,
Vlahopoulos
,
N.
, and
Vaidyanathan
,
K.
,
2004
, “
Calculation of Journal Bearing Dynamic Characteristics Including Journal Misalignment and Bearing Structural Deformation
,”
Tribol. Trans.
,
47
(
1
), pp.
94
102
. 10.1080/05698190490278994
22.
Ahmed
,
A. M.
, and
El-Shafei
,
A.
,
2008
, “
Effect of Misalignment on the Characteristics of Journal Bearings
,”
ASME J. Eng. Gas Turbines Power
,
130
(
4
), p.
042501
. 10.1115/1.2800347
23.
Lee
,
D.
,
Sun
,
K.
,
Kim
,
B.
, and
Kang
,
D.
,
2017
, “
Thermal Behavior of a Worn Tilting Pad Journal Bearing: Thermohydrodynamic Analysis and Pad Temperature Measurement
,”
Tribol. Trans.
,
61
(
6
), pp.
1074
1083
. 10.1080/10402004.2018.1469805
24.
Sim
,
K.
, and
Kim
,
D.
,
2008
, “
Thermohydrodynamic Analysis of Compliant Flexure Pivot Tilting Pad Gas Bearings
,”
ASME J. Eng. Gas Turbines Power
,
130
(
3
), p.
032502
. 10.1115/1.2836616
25.
Khonsari
,
M. M.
, and
Booser
,
E. R.
,
2017
,
Applied Tribology: Bearing Design and Lubrication
,
John Wiley & Sons
,
New York
.
26.
Heinrich
,
J.
,
Huyakorn
,
P.
,
Zienkiewicz
,
O.
, and
Mitchell
,
A.
,
1977
, “
An ‘Upwind’ Finite Element Scheme for Two-Dimensional Convective Transport Equation
,”
Int. J. Numer. Methods Eng.
,
11
(
1
), pp.
131
143
. 10.1002/nme.1620110113
27.
ISO
,
2010
,
Geometrical Product Specifications (GPS)-ISO Code System for Tolerances on Linear Size—Part 1: Basis of Tolerances, Deviations and Fits
,
International Organization for Standardization
,
Geneva, Switzerland
.
You do not currently have access to this content.