Abstract

Traditional bump foil bearing, though widely used, is considered to have the problem of inadequate load capacity due to the effect of foil sag between adjacent bumps. In this paper, the thick top foil is applied to cope with the heavy load conditions, which has one order of magnitude larger top foil thickness than traditional top foil. Thick plate and curve shell models are developed to calculate the load-carrying performance of thick top foil bearing based on contact mechanics, and the sag ratio is introduced to describe the degree of foil sag and estimate the bearing load capacity. The impacts of top foil thickness on the stiffness of bearings in different sizes as well as on the adaptability to rotor tilt are discussed. The results indicate that the thick top foil (tt = 2 mm) bearing performs a nearly 100% enhanced load capacity at small gas film thickness whether rotor tilts or not. Thick top foil will increase the bearing stiffness of small size (d = 35 mm) and tends to have little influence on large-size bearing stiffness (d = 70 mm).

References

1.
Barnett
,
M. A.
, and
Silver
,
A.
,
1970
, “
Application of Air Bearings to High-Speed Turbomachinery
,” SAE Technical Paper No. 700720.
2.
Dellacorte
,
C.
,
Zaldana
,
A. R.
, and
Radil
,
K. C.
,
2004
, “
A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery
,”
ASME J. Tribol.
,
126
(
1
), pp.
200
207
.
3.
Dellacorte
,
C.
, and
Valco
,
M. J.
,
2000
, “
Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications
,”
Tribol. Trans.
,
43
(
4
), pp.
795
801
.
4.
Zhao
,
X.
, and
Xiao
,
S.
,
2021
, “
A Three-Dimensional Model of Gas Foil Bearings and the Effect of Misalignment on the Static Performance of the First and Second Generation Foil Bearings
,”
Tribol. Int.
,
156
(
3
), p.
106821
.
5.
Heshmat
,
H.
,
1994
, “
Advancements in the Performance of Aerodynamic Foil Journal Bearings: High Speed and Load Capability
,”
ASME J. Tribol.
,
116
(
2
), pp.
287
295
.
6.
Feng
,
K.
,
Zhang
,
T.
, and
Zhao
,
X.
,
2017
, “
Experiments and Predictions on the Performance of Double-Bump Foil Bearings: Effects of Bearing Loads and Height Difference Between Bumps
,”
Proc. Inst. Mech. Eng. Part J J. Eng. Tribol.
,
231
(
11
), pp.
1474
1485
.
7.
Xu
,
Z.
,
Li
,
C.
, and
Du
,
J.
,
2021
, “
Modeling and Static Characteristics Study of the Double-Layer Bump Gas Foil Bearing
,”
Tribol. Int.
,
164
(
12
), p.
107202
.
8.
Yan
,
J.
,
Zhang
,
G.
,
Liu
,
Z.
,
Zhao
,
J.
, and
Xu
,
L.
, “
Performance of a Novel Foil Journal Bearing With Surface Micro-Grooved Top Foil
,”
Proc. Inst. Mech. Eng. Part J J. Eng. Tribol.
,
232
(
9
), pp.
1126
1139
.
9.
Xu
,
F.
,
Kim
,
D.
, and
Zamanian Yazdi
,
B.
,
2016
, “
Theoretical Study of Top Foil Sagging Effect on the Performance of Air Thrust Foil Bearing
,”
Proceedings of the ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. Volume 7B: Structures and Dynamics
,
Seoul, South Korea
,
June 13–17
,
ASME
, p.
V07BT31A013
.
10.
Heshmat
,
H.
,
Walowit
,
J. A.
, and
Pinkus
,
O.
,
1983
, “
Analysis of Gas Lubricated Compliant Thrust Bearings
,”
ASME J. Lubr. Technol.
,
105
(
4
), pp.
638
646
.
11.
Heshmat
,
H.
,
Walowit
,
J. A.
, and
Pinkus
,
O.
,
1983
, “
Analysis of Gas-Lubricated Foil Journal Bearings
,”
ASME J. Lubr. Technol.
,
105
(
4
), pp.
647
655
.
12.
Roger Ku
,
C. P.
, and
Heshmat
,
H.
,
1992
, “
Compliant Foil Bearing Structural Stiffness Analysis: Part I—Theoretical Model Including Strip and Variable Bump Foil Geometry
,”
ASME J. Tribol.
,
114
(
2
), pp.
394
400
.
13.
Roger Ku
,
C. P.
, and
Heshmat
,
H.
,
1993
, “
Compliant Foil Bearing Structural Stiffness Analysis—Part II: Experimental Investigation
,”
ASME J. Tribol.
,
115
(
3
), pp.
364
369
.
14.
Heshmat
,
C. A.
,
Xu
,
D. S.
, and
Heshmat
,
H.
,
2000
, “
Analysis of Gas Lubricated Foil Thrust Bearings Using Coupled Finite Element and Finite Difference Methods
,”
ASME J. Tribol.
,
122
(
1
), pp.
199
204
.
15.
Iordanoff
,
I.
,
1999
, “
Analysis of an Aerodynamic Compliant Foil Thrust Bearing: Method for a Rapid Design
,”
ASME J. Tribol.
,
121
(
4
), pp.
816
822
.
16.
Le Lez
,
S.
,
Arghir
,
M.
, and
Frene
,
J.
,
2007
, “
A New Bump-Type Foil Bearing Structure Analytical Model
,”
ASME J. Eng. Gas Turbines Power
,
129
(
4
), pp.
747
757
.
17.
Lee
,
Y. B.
,
Park
,
D. J.
,
Kim
,
C. H.
, et al
,
2008
, “
Operating Characteristics of the Bump Foil Journal Bearings With Top Foil Bending Phenomenon and Correlation among Bump Foils
,”
Tribol. Int.
,
41
(
4
), pp.
221
233
.
18.
Larsen
,
J. S.
,
Varela
,
A. C.
, and
Santos
,
I. F.
,
2014
, “
Numerical and Experimental Investigation of Bump Foil Mechanical Behaviour
,”
Tribol. Int.
,
74
(
6
), pp.
46
56
.
19.
Gu
,
Y.
,
Ren
,
G.
, and
Zhou
,
M.
,
2020
, “
A Fully Coupled Elastohydrodynamic Model for Static Performance Analysis of Gas Foil Bearings
,”
Tribol. Int.
,
147
(
5
), p.
106297
.
20.
Lee
,
D. H.
,
Kim
,
Y. C.
, and
Kim
,
K. W.
,
2008
, “
The Static Performance Analysis of Foil Journal Bearings Considering Three-Dimensional Shape of the Foil Structure
,”
ASME J. Tribol.
,
130
(
3
), pp.
1
10
.
21.
Gu
,
Y.
,
Lan
,
X.
,
Ren
,
G.
, and
Zhou
,
M.
,
2021
, “
An Efficient Three-Dimensional Foil Structure Model for Bump-Type Gas Foil Bearings Considering Friction
,”
Friction
,
9
(
6
), pp.
1450
1463
.
22.
Lee
,
D. H.
,
Kim
,
Y. C.
, and
Kim
,
K. W.
,
2010
, “
The Effect of Coulomb Friction on the Static Performance of Foil Journal Bearings
,”
Tribol. Int.
,
43
(
5–6
), pp.
1065
1072
.
23.
Gad
,
A. M.
, and
Kaneko
,
S.
,
2014
, “
A New Structural Stiffness Model for Bump-Type Foil Bearings: Application to Generation II gas Lubricated Foil Thrust Bearing
,”
ASME J. Tribol.
,
136
(
4
), p.
041701
.
24.
Li
,
C.
,
Du
,
J.
, and
Yao
,
Y.
,
2017
, “
Modeling of a Multi-Layer Foil gas Thrust Bearing and its Load Carrying Mechanism Study
,”
Tribol. Int.
,
114
(
10
), pp.
172
185
.
25.
Li
,
C.
,
Du
,
J.
,
Zhu
,
J.
, and
Yao
,
Y.
,
2019
, “
Effects of Structural Parameters on the Load Carrying Capacity of the Multi-Leaf Gas Foil Journal Bearing Based on Contact Mechanics
,”
Tribol. Int.
,
131
(
3
), pp.
318
331
.
26.
Li
,
C.
,
Du
,
J.
, and
Yao
,
Y.
,
2020
, “
Study of Load Carrying Mechanism of a Novel Three-Pad Gas Foil Bearing With Multiple Sliding Beams
,”
Mech. Syst. Signal Process.
,
135
(
1
), p.
106372
.
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