Although gas-lubricated herringbone grooved journal bearings (HGJB) are known for high rotordynamic stability thresholds, small clearance to diameter ratios are required for stable rotor operation. Tight clearances not only increase bearing losses but also yield challenging manufacturing and assembly tolerances, which ultimately translate into cost. Traditionally, the grooves of HGJB are of helical nature with constant cross section and pitch. The current paper aims at increasing the clearance to diameter ratio and the stability threshold of grooved bearings by introducing enhanced groove geometries. The axial evolution of groove width, depth, and local pitch are described by individual third order polynomials with four interpolation points. The expression for the smooth pressure distribution resulting from the narrow groove theory is modified to enable the calculation of bearing properties with modified groove patterns. The reduced order bearing model is coupled to a linear rigid body rotordynamic model for predicting the whirl speed map and the corresponding stability. By introducing a critical mass parameter as a measure for stability, a criterion for the instability onset is proposed. The optimum groove geometry is found by coupling the gas bearing supported rotor model with a multiobjective optimizer. By maximizing both the clearance to diameter ratio and the rotordynamic stability it is shown that with optimal groove geometry, which deviates from helicoids with constant pitch and cross section, the critical mass parameter can be improved by more than one order of magnitude compared to traditional HGJB geometries. The clearance to diameter ratio can be increased by up to 80% while keeping the same stability margin, thus reducing both losses and manufacturing constraints. The optimum groove pattern distributions (width ratio, angle, and depth) are summarized for a variety of L/D ratios and for different compressibility numbers in a first attempt to set up general design guidelines for enhanced gas-lubricated HGJB.

References

References
1.
Balje
,
O. E.
,
1981
,
Turbomachines, A Guide to Design, Selection and Theory
,
John Wiley and Sons
,
New York
.
2.
Miller
,
T. J. E.
,
1993
,
Switched Reluctance Motors and Their Control
,
Magna Physics Publishing Oxford Science Publications
,
Oxford, UK
.
3.
Czolczinski
,
K.
, and
Marynowski
,
K.
,
1996
, “
Stability of Symmetrical Rotor Supported in Flexibly Mounted, Self-Acting Gas Journal Bearings
,”
Wear
,
194
(1–2), pp.
190
197
.10.1016/0043-1648(95)06843-0
4.
Czolczinski
,
K.
, and
Marynowski
,
K.
,
1996
, “
Stability of Symmetrical Rotor Supported in Flexibly Mounted, Self-Acting Gas Journal Bearings
,”
Wear
,
194
, pp.
190
197
.10.1016/0043-1648(95)06843-0
5.
Schiffmann
,
J.
, and
Favrat
,
D.
,
2010
, “
Design, Experimental Investigation and Multi-Objective Optimization of a Small-Scale Radial Compressor for Heat Pump Applications
,”
Energy
,
35
, pp.
436
450
.10.1016/j.energy.2009.10.010
6.
Fuller
,
D. D.
,
1969
, “
A Review of the State-of-the-Art for the Design of Self-Acting Gas-Lubricated Bearings
,”
J. Lub. Technol.
,
91
, pp.
1
16
.10.1115/1.3554857
7.
Schiffmann
,
J.
, and
Favrat
,
D.
,
2009
, “
Experimental Investigation of a Direct Driven Radial Compressor for Domestic Heat Pumps
,”
Int. J. Refrig.
,
32
, pp.
1918
1928
.10.1016/j.ijrefrig.2009.07.006
8.
Schiffmann
,
J.
, and
Favrat
,
D.
,
2010
, “
Integrated Design and Optimization of Gas Bearing Supported Rotors
,”
ASME J. Mech. Design
,
132
, p.
051007
.10.1115/1.4001381
9.
Pan
,
C. H. T.
,
1964
, “
Spectral Analysis of Gas Bearing Systems for Stability Studies
,” Mechanical Technology Inc., Latham, NY, Technical Report No. MTI 64TR58.
10.
Pan
,
C. H. T.
, and
Kim
,
D.
,
2007
, “
Stability Characteristics of a Rigid Rotor Supported by a Gas-Lubricated Spiral-Groove Conical Bearing
,”
ASME J. Tribol.
,
129
, pp.
375
383
.10.1115/1.2647443
11.
Faria
,
M. T. C.
,
2001
, “
Some Performance Characteristics of High Speed Gas Lubricated Herringbone Groove Journal Bearings
,”
JSME Int. J., Ser. C
,
44
, pp.
775
781
.10.1299/jsmec.44.775
12.
Bonneau
,
D.
, and
Absi
,
J.
,
1994
, “
Analysis of Aerodynamic Journal Bearings With Small Number of Herringbone Grooves by Finite Element Method
,”
ASME J. Tribol.
,
116
, pp.
698
704
.10.1115/1.2927320
13.
Gross
,
W. A.
,
Matsch
,
L. A.
,
Castelli
,
V.
,
Eshel
,
A.
,
Vohr
,
J. H.
, and
Wildmann
,
M.
,
1962
,
Gas Film Lubrication
,
John Wiley and Sons
,
New York
.
14.
Vohr
,
J. H.
, and
Chow
,
C. Y.
,
1965
, “
Characteristics of Herringbone-Grooved, Gas-Lubricated Journal Bearings
,”
J. Basic Eng.
,
87
, pp.
568
578
.10.1115/1.3650607
15.
Lund
,
J. W.
,
1968
, “
Calculation of Stiffness and Damping Properties of Gas Bearings
,”
J. Lub. Technol.
,
90
, pp.
783
803
.10.1115/1.3601723
16.
Schiffmann
,
J.
, and
Spakovszky
,
Z. S.
,
2013
, “
Foil Bearing Design Guidelines for Improved Stability
,”
ASME J. Tribol.
,
135
, p.
011103
.10.1115/1.4007759
17.
Szeri
,
A.
,
1980
,
Tribology: Friction, Lubrication and Wear
,
McGraw-Hill
,
New York
.
18.
Schiffmann
,
J.
, and
Favrat
,
D.
,
2010
, “
The Effect of Real Gas on the Properties of Herringbone Grooved Journal Bearings
,”
Tribol. Int.
,
43
, pp.
1602
1614
.10.1016/j.triboint.2010.03.006
19.
Molyneaux
,
A.
,
Leyland
,
G. B.
, and
Favrat
,
D.
,
2010
, “
Environomic Multi-Objective Optimization of a District Heating Network Considering Centralized and Decentralized Heat Pumps
,”
Energy
,
35
, pp.
751
758
.10.1016/j.energy.2009.09.028
20.
Cunningham
,
R. E.
,
Fleming
,
D. P.
, and
Anderson
,
W. J.
,
1971
, “
Experimental Load Capacity and Power Loss of Herringbone Grooved Gas Lubricated Journal Bearings
,”
J. Lub. Technol.
,
93
, pp.
415
422
.10.1115/1.3451610
21.
Meijer
,
J.
,
2004
, “
Laser Beam Machining (LBM), State of the Art and New Opportunities
,”
J. Mater. Process. Technol.
,
149
, pp.
2
17
.10.1016/j.jmatprotec.2004.02.003
22.
Dumitru
,
G.
,
Lüscher
,
B.
,
Krack
,
M.
,
Bruneau
,
S.
,
Hermann
,
J.
, and
Gerbig
,
Y.
,
2005
, “
Laser Processing of Hardmetals: Physical Basis and Applications
,”
Int. J. Refractory Metals Hard Mater.
,
23
, pp.
278
286
.10.1016/j.ijrmhm.2005.04.020
23.
Weber
,
V. S. P.
, and
Ruhs
,
C.
,
2012
, “
Increase of Process Reliability in the Micro-Machining Processes EDM-Milling and Laser Ablation Using On-Machine Sensors
,”
J. Mater. Process. Technol.
,
121
, pp.
625
632
.10.1016/j.jmatprotec.2011.09.014
24.
Heyl
,
P.
,
Oschewski
,
T.
, and
Wijnaendts
,
R. W.
,
2001
, “
Manufacturing of 3D Structures for Micro-Tools Using Laser Ablation
,”
Microelectron. Eng.
,
57–58
, pp.
775
780
.10.1016/S0167-9317(01)00485-3
You do not currently have access to this content.