Abstract

Hydrostatic journal bearings (HJBs), employed in high-speed turbomachinery under extreme operating conditions, offer enhanced reliability, durability, load-carrying capacity, and stiffness, even when lubricated with low-viscosity fluids. A significant challenge with these bearings, particularly when deep recesses are involved and compressible fluids are used, is the occurrence of pneumatic hammer instability. This phenomenon poses a substantial risk, potentially leading to catastrophic system failures. The focus of this research is to quantify the influence of orifice diameter and recess depth on pneumatic hammer instability in HJBs. The study employs a predictive model, prioritizing the understanding and mitigation of this instability. Key to this research is the examination of volume and pressure ratios, particularly the recess volume to fluid film volume ratio and the recess pressure to supply pressure ratio. These ratios are fundamentally influenced by the orifice diameter and recess depth, which in turn significantly affect the HJBs' characteristics and susceptibility to pneumatic hammer instability. The current study reveals that both the load-carrying capacity and flow rate of the bearings increase progressively with the recess pressure ratio. Meanwhile, the bearing stiffness peaks at a specific orifice diameter and recess depth, typically where the recess pressure ratio is around 0.6. Under these conditions, the bearings demonstrate maximum stiffness with minimized risk of instability. This research also proposes a framework for selecting design parameters in HJBs, aiming to maximize stiffness while averting pneumatic hammer instability. The effectiveness of these design strategies is validated through experimental data from two test bearings, each with different recess depths and orifice diameters. This work contributes significantly to the field by offering strategies for optimizing HJBs. It provides a balance between achieving high performance and mitigating the risks associated with pneumatic hammer instability. By careful selection of orifice diameter and recess depth, it is possible to attain maximum bearing performance, effectively circumventing the challenges posed by pneumatic hammer instability.

References

1.
Ghosh
,
M. K.
, and
Viswanath
,
N. S.
,
1987
, “
Recess Volume Fluid Compressibility Effect on the Dynamic Characteristics of Multirecess Hydrostatic Journal Bearings With Journal Rotation
,”
ASME J. Tribol.
,
109
(
3
), pp.
417
426
.10.1115/1.3261462
2.
Chen
,
X. D.
, and
He
,
X. M.
,
2006
, “
The Effect of the Recess Shape on Performance Analysis of the Gas-Lubricated Bearing in Optical Lithography
,”
Tribol. Int.
,
39
(
11
), pp.
1336
1341
.10.1016/j.triboint.2005.10.005
3.
Bassani
,
R.
,
Ciulli
,
E.
, and
Forte
,
P.
,
1989
, “
Pneumatic Stability of the Integral Aerostatic Bearing: Comparison With Other Types of Bearing
,”
Tribol. Int.
,
22
(
6
), pp.
363
374
.10.1016/0301-679X(89)90068-6
4.
Rowe
,
B. W.
,
2012
,
Hydrostatic, Aerostatic and Hybrid Bearing Design
,
Elsevier Science
, Amsterdam,
The Netherlands
.
5.
Powell
,
J. W.
,
1970
,
Design of Aerostatic Bearings
,
The Machinery Publishing
,
Brighton, UK
.
6.
Lund
,
J. W.
,
1967
, “
A Theoretical Analysis of Whirl Instability and Pneumatic Hammer for a Rigid Rotor in Pressurized Gas Journal Bearings
,”
ASME J. Lubr. Technol.
,
89
(
2
), pp.
154
165
.10.1115/1.3616933
7.
Blondeel
,
E.
,
Snoeys
,
R.
, and
Devrieze
,
L.
,
1980
, “
Dynamic Stability of Externally Pressurized Gas Bearings
,”
ASME J. Lubr. Technol.
,
102
(
4
), pp.
511
519
.10.1115/1.3251588
8.
San Andrés
,
L.
,
1991
, “
Effects of Fluid Compressibility on the Dynamic Response of Hydrostatic Journal Bearings
,”
Wear
,
146
(
2
), pp.
269
283
.10.1016/0043-1648(91)90068-6
9.
Talukder
,
H. M.
, and
Stowell
,
T. B.
,
2003
, “
Pneumatic Hammer in an Externally Pressurized Orifice-Compensated Air Journal Bearing
,”
Tribol. Int.
,
36
(
8
), pp.
585
591
.10.1016/S0301-679X(02)00247-5
10.
Wang
,
P.
,
Zhang
,
Y.
,
Feng
,
L.
,
Hou
,
W.
,
Wang
,
J.
,
Li
,
W.
, and
Feng
,
K.
,
2023
, “
Study on the Pneumatic Hammer Phenomenon of Aerostatic Bearings Based on the Empirical Mode Method: Numerical and Experimental Analysis
,”
Tribol. Int.
,
181
, p.
108305
.10.1016/j.triboint.2023.108305
11.
Arghir
,
M.
,
Hassini
,
M. A.
,
Balducchi
,
F.
, and
Gauthier
,
R.
,
2016
, “
Synthesis of Experimental and Theoretical Analysis of Pneumatic Hammer Instability in an Aerostatic Bearing
,”
ASME J. Eng. Gas Turbines Power
,
138
(
2
), p.
021602
.10.1115/1.4031322
12.
Roblee
,
J. W.
, and
Mote
,
C. D.
, Jr.
,
1990
, “
Design of Externally Pressurized Gas Bearings for Stiffness and Damping
,”
Tribol. Int.
,
23
(
5
), pp.
333
345
.10.1016/0301-679X(90)90007-C
13.
Hassini
,
M. A.
,
Arghir
,
M.
, and
Frocot
,
M.
,
2012
, “
Comparison Between Numerical and Experimental Dynamic Coefficients of a Hybrid Aerostatic Bearing
,”
ASME J. Eng. Gas Turbines Power
,
134
(
12
), p.
122506
.10.1115/1.4007375
14.
Belforte
,
G.
,
Raparelli
,
T.
,
Viktorov
,
V.
, and
Trivella
,
A.
,
2007
, “
Discharge Coefficients of Orifice-Type Restrictor for Aerostatic Bearings
,”
Tribol. Int.
,
40
(
3
), pp.
512
521
.10.1016/j.triboint.2006.05.003
15.
Belforte
,
G.
,
Colombo
,
F.
,
Raparelli
,
T.
,
Trivella
,
A.
, and
Viktorov
,
V.
,
2010
, “
Performance of Externally Pressurized Grooved Thrust Bearings
,”
Tribol. Lett.
,
37
(
3
), pp.
553
562
.10.1007/s11249-009-9550-3
16.
Belforte
,
G.
,
Colombo
,
F.
,
Raparelli
,
T.
,
Trivella
,
A.
, and
Viktorov
,
V.
,
2011
, “
Comparison Between Grooved and Plane Aerostatic Thrust Bearings: Static Performance
,”
Meccanica
,
46
(
3
), pp.
547
555
.10.1007/s11012-010-9307-y
17.
Hibbs
,
R.
, Jr.
,
Scharrer
,
J. K.
, and
Molvik
,
G. L.
,
1996
, “
Turbulent Hydrostatic Thrust Bearings: Part 1—Bulk-Flow Analysis for Performance and Pneumatic Hammer
,”
AIAA
Paper No. 96-2741.10.2514/6.96-2741
18.
Pelfrey
,
P. C.
, and
Sishtla
,
V. M.
,
1996
, “
Investigation of Hydrostatic Bearings Operating in a Turbulent, Compressible Liquid
,”
AIAA
Paper No. 96-3103.10.2514/6.96-3103
19.
Delgado
,
A.
, and
Ertas
,
B.
,
2018
, “
Dynamic Force Coefficients of Hydrostatic Gas Films for Recessed Float Plates: Experimental Identification and Numerical Predictions
,”
ASME J. Tribol.
,
140
(
6
), p.
061703
.10.1115/1.4040114
20.
Jung
,
H.
,
Sin
,
S.
,
Kim
,
K.
,
Heo
,
J.
,
Wee
,
M.
, and
Ryu
,
K.
,
2022
, “
On the Pneumatic Hammer of Hybrid Gas Bearings: Measurements and Predictions
,”
ASME J. Eng. Gas Turbines Power
,
144
(
12
), p.
121011
.10.1115/1.4055485
21.
Jung
,
H.
,
Kim
,
K.
, and
Ryu
,
K.
,
2023
, “
On the Performance of Hydrostatic Journal Bearings in Air, Water, and Liquid Nitrogen: Measurements and Predictions
,”
ASME J. Eng. Gas Turbines Power
,
145
(
11
), p.
111011
.10.1115/1.4063282
22.
San Andrés
,
L.
, and
Wilde
,
D.
,
2001
, “
Finite Element Analysis of Gas Bearings for Oil-Free Turbomachinery
,”
Revne Eur. Elém. Finis
,
10
(
6–7
), pp.
769
790
.10.1080/12506559.2001.9737570
23.
San Andrés
,
L. A.
,
1992
, “
Analysis of Hydrostatic Journal Bearings With End Seals
,”
ASME J. Tribol.
,
114
(
4
), pp.
755
764
.10.1115/1.2920945
24.
San Andrés
,
L.
,
2009
, “
Hydrostatic Bearings
,”
Modern Lubrication Theory, Notes 12(b)
,
Libraries Texas A&M University Repository, Texas A&M University Library
,
College Station, TX
.
25.
Reddecliff
,
J. M.
, and
Vohr
,
J. H.
,
1969
, “
Hydrostatic Bearings for Cryogenic Rocket Engine Turbopumps
,”
ASME J. Lubr. Technol.
,
91
(
3
), pp.
557
575
.10.1115/1.3554989
You do not currently have access to this content.