This paper presents simulation results corresponding with the theoretical Morton effect model explained in Part I, where the 3D finite element models of bearing, shaft, and fluid film are adopted. In addition, it explains how thermal bow induced imbalance force develops in the spinning journal with time and how the vibration level is affected by the thermal bow vector. Shaft asymmetric thermal expansion induced by nonuniform journal heating is simulated, which is one of the unique contributions of this research. The effect of changes in: (1) thermal boundary condition around the pad, (2) lubricant supply temperature, (3) initial mechanical imbalance, (4) pivot stiffness, (5) film clearance, and (6) pad material are studied. Cooling the pad and the lubricant, using a pad with a low thermal expansion coefficient, soft pivot, and reducing the initial imbalance are found to be the best remedies for the thermal induced synchronous rotor instability problem.

References

References
1.
De Jongh
,
F.
,
Morton
,
P.
, and
Holmes
,
R.
,
1996
, “
The Synchronous Instability of a Compressor Rotor Due to Bearing Journal Differential Heating
,”
ASME J. Eng. Gas Turbines Power
,
118
(
4
), pp.
816
824
.10.1115/1.2816998
2.
De Jongh
,
F. M.
, and
van der Hoeven
,
P.
,
1998
, “
Application of a Heat Barrier Sleeve to Prevent Synchronous Rotor Instability
,”
Proceedings of the 27th Turbomachinery Symposium
, pp.
17
26
.
3.
Gomiciaga
,
R.
, and
Keogh
,
P.
,
1999
, “
Orbit Induced Journal Temperature Variation in Hydrodynamic Bearings
,”
ASME J. Tribol.
,
121
(
1
), pp.
77
84
.10.1115/1.2833814
4.
Childs
,
D. W.
, 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
.10.1115/1.4005973
5.
Lee
,
J. G.
, and
Palazzolo
,
A.
,
2013
, “
Morton Effect Cyclic Vibration Amplitude Determination for Tilt Pad Bearing Supported Machinery
,”
ASME J. Tribol.
,
135
(
1
), p.
011701
.10.1115/1.4007884
6.
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
.
7.
Murphy
,
B. T.
, and
Lorenz
,
J. A.
,
2010
, “
Simplified Morton Effect Analysis for Synchronous Spiral Instability
,”
ASME J. Vibr. Acoust.
,
132
(
5
), p.
051008
.10.1115/1.4001512
8.
Morton
,
P. G.
,
2007
, “
The Morton Effect and Light Rubs in Rotating Machinery
,”
Orbit
,
27
(
1
), pp.
44
51
.
9.
Larsson
,
B.
,
1999
, “
Journal Asymmetric Heating. Part I: Nonstationary Bow
,”
ASME J. Tribol.
,
121
(
1
), pp.
157
163
.10.1115/1.2833797
10.
Larsson
,
B.
,
1999
, “
Journal Asymmetric Heating. Part II: Alteration of Rotor Dynamic Properties
,”
ASME J. Tribol.
,
121
(
1
), pp.
164
168
.10.1115/1.2833798
You do not currently have access to this content.