The aim of the present study is to develop a design guideline to improve the load capacity of gas foil thrust bearings (GFTBs). The Reynolds equation for an isothermal isoviscous ideal gas calculates the gas film pressure. The film pressure averaged in the radial direction determines the ultimate load capacity. The load capacity, film pressure profile, and film thickness profile are predicted for a GFTB with an outer radius of 55 mm, inner radius of 30 mm, and eight foils each of arc length 45 deg. The predictions show that the load capacity of the GFTB increases with increasing rotor speed and decreasing minimum film thickness. A parametric study, in which the ramp extent (or inclined angle) is increased from 5 deg to 40 deg, and the ramp height from 0 to 320 μm, reveals that GFTBs have an optimal ramp extent of ∼22.5 deg and ramp height of 30 μm for maximum load capacity. A series of maximum load capacity measurements are conducted on four test GFTBs with ramp heights of 50, 150, 250, and 350 μm at the speeds of 12, 15, and 18 krpm. To estimate the maximum load capacity, the applied load is increased until the drag torque rises suddenly with a sharp peak. The test results show that the maximum load capacity generally increases for decreasing ramp height and for increasing rotor speed. The GFTB with a ramp height of 50 μm shows the largest maximum load capacity of 510 N, for example. Test results are in good agreement with model predictions.

References

References
1.
Heshmat
,
H.
,
Walowit
,
J. A.
, and
Pinkus
,
O.
,
1983
, “
Analysis of Gas Lubricated Compliant Thrust Bearings
,”
ASME J. Tribol.
,
105
(
4
), pp.
638
646
.
2.
Iordanoff
,
I.
,
1999
, “
Analysis of an Aerodynamic Compliant Foil Thrust Bearing: Method for a Rapid Design
,”
ASME J. Tribol.
,
121
(
4
), pp.
816
822
.
3.
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
.
4.
Bruckner
,
R. J.
,
DellaCorte
,
C.
, and
Prahl
,
J. M.
,
2005
, “
Analytic Modeling of the Hydrodynamic, Thermal, and Structural Behavior of Foil Thrust Bearings
,” Report No.
NASA
/TM-2005-213811.
5.
Park
,
D.-J.
,
Kim
,
C.-H.
,
Jang
,
G.-H.
, and
Lee
,
Y.-B.
,
2007
, “
Theoretical Considerations of Static and Dynamic Characteristics of Air Foil Thrust Bearing With Tilt and Slip Flow
,”
Tribol. Int.
,
41
(
4
), pp.
282
295
.
6.
Zhou
,
Q.
,
Hou
,
Y.
,
Chen
,
R.
,
Chen
,
S.
, and
Chen
,
C.
,
2010
, “
Static Analysis of Viscoelastic Supported Gas Foil Thrust Bearing With Journal Inclination
,”
J. Adv. Mech. Des. Syst.
,
4
(
7
), pp.
1210
1220
.
7.
Kim
,
T. H.
,
Lee
,
Y. B.
,
Kim
,
T. Y.
, and
Jeong
,
K. H.
,
2012
, “
Rotordynamic Performance of an Oil-Free Turbo Blower Focusing on Load Capacity of Gas Foil Thrust Bearings
,”
ASME J. Eng. Gas Turbines Power
,
134
(
2
), p.
022501
.
8.
Lee
,
Y. B.
,
Kim
,
T. Y.
,
Kim
,
C. H.
, and
Kim
,
T. H.
,
2011
, “
Thrust Bump Air Foil Bearings With Variable Axial Load: Theoretical Predictions and Experiments
,”
STLE Tribol. Trans.
,
54
(
6
), pp.
902
910
.
9.
Lee
,
D.
, and
Kim
,
D.
,
2011
, “
Three-Dimensional Thermohydrodynamic Analyses of Rayleigh Step Air Foil Thrust Bearing With Radially Arranged Bump Foils
,”
STLE Tribol. Trans.
,
54
(
3
), pp.
432
448
.
10.
Lee
,
D.
, and
Kim
,
D.
,
2011
, “
Design and Performance Prediction of Hybrid Air Foil Thrust Bearings
,”
ASME J. Eng. Gas Turbines Power
,
133
(
4
), p.
042501
.
11.
Balducchi
,
F.
,
Arghir
,
M.
,
Gauthier
,
R.
, and
Renard
,
E.
,
2013
, “
Experimental Analysis of the Start-Up Torque of a Mildly Loaded Foil Thrust Bearing
,”
ASME J. Tribol.
,
135
(
3
), p.
031702
.
12.
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
.
13.
San Andrés
,
L.
,
Ryu
,
K.
, and
Diemer
,
P.
,
2014
, “
Prediction of Gas Thrust Foil Bearing Performance for Oil-Free Automotive Turbochargers
,”
ASME J. Eng. Gas Turbines Power
,
137
(
3
), p.
032502
.
14.
Kim
,
T. H.
, and
San Andrés
,
L.
,
2008
, “
Heavily Loaded Gas Foil Bearings: A Model Anchored to Test Data
,”
ASME J. Eng. Gas Turbines Power
,
130
(
1
), p.
012504
.
15.
Kim
,
T. H.
, and
San Andrés
,
L.
,
2006
, “
Limits for High-Speed Operation of Gas Foil Bearings
,”
ASME J. Tribol.
,
128
(
3
), pp.
670
673
.
16.
Jung
,
S. Y.
,
2009
, “
The Limiting Load Capacity of Air Foil Thrust Bearings
,”
J. Korean Soc. Tribol. Lubr. Eng.
,
25
(
5
), pp.
279
284
.
17.
Kim
,
T. H.
,
Lee
,
T. W.
,
Park
,
M. S.
,
Park
,
J.
,
Kim
,
J.
, and
Jeong
,
J.
,
2015
, “
Experimental Study on the Load Carrying Performance and Driving Torque of Gas Foil Thrust Bearings
,”
J. Korean Soc. Tribol. Lubr. Eng.
,
31
(
4
), pp.
141
147
.
18.
Sim
,
K.
,
Lee
,
J.
,
Lee
,
Y.-B.
, and
Kim
,
T. H.
,
2012
, “
Rotordynamic Performance of Shimmed Gas Foil Bearings for Oil-Free Turbochargers
,”
ASME J. Tribol.
,
134
(
3
), p.
031102
.
19.
Kim
,
T. H.
,
Lee
,
J.
, and
Kim
,
Y. M.
,
2015
, “
Static Structural Characterization of Multilayer Gas Foil Journal Bearings
,”
ASME
Paper No. GT2015-43999.
20.
Ruscitto
,
D.
,
Mc Cormick
,
J.
, and
Gray
,
S.
,
1978
, “
Hydrodynamic Air Lubricated Compliant Surface Bearing for an Automotive Gas Turbine Engine I-Journal Bearing Performance
,”
NASA
Report No. CR-135368.
21.
Dickman
,
J. R.
,
2010
, “
An Investigation of Gas Foil Thrust Bearing Performance and its Influencing Factors
,”
MS thesis
, Case Western Reserve University, Cleveland, OH.
22.
San Andrés
,
L.
, and
Kim
,
T. H.
,
2009
, “
Analysis of Gas Foil Bearings Integrating FE Top Foil Models
,”
Tribol. Int.
,
42
(
1
), pp.
111
120
.
23.
Maru
,
M. M.
, and
Tanaka
,
D. K.
,
2007
, “
Consideration of Stribeck Diagram Parameters in the Investigation on Wear and Friction Behavior in Lubricated Sliding
,”
ABCM J. Braz. Soc. Mech. Sci. Eng.
,
29
(
1
), pp.
55
62
.
24.
Hutchings
,
I. M.
,
1992
,
Tribology: Friction and Wear of Engineering Materials
,
Edward Arnold
,
London, UK
.
You do not currently have access to this content.