A microbearing tester driven by an air turbine of 10mm diameter has been developed, and successfully used to test hydroinertia gas bearings with a shaft of 4mm diameter. The effects of bearing gas pressure conditions and bearing length to diameter ratio (L∕D) on the maximum achievable rotation speed were investigated. The maximum rotation speed of 890,000rpm⁠, which corresponds to the DN number (the product of a shaft diameter in millimeter and a rotation speed in rpm) of 3,560,000, was achieved. At 890,000rpm⁠, the tip speed of the turbine reaches approximately 470m∕s⁠. Using the bearing system developed, the turbo components of a 100W class gas turbine and an air pump for 1kW class fuel cells can be tested.

Issue Section:
Technical Papers
Keywords:
hydroinertia gas bearing, high-speed bearing, microturbomachinery, turbine, machine bearings, impellers, micromechanical devices, shafts, gas turbines, mechanical testing, hydrostatics
Topics:
Bearings, Gas bearings, Impellers, Pressure, Rotation, Rotors, Journal bearings, Hydrostatics, Clearances (Engineering), Turbines
1.
Epstein
,
A. H.
, 2003, “
Millimeter-Scale, Micro-Electro-Mechanical Systems Gas Turbine Engines
,”
Trans. ASME: J. Eng. Gas Turbines Power
0742-4795,
126
, pp.
205
–
226
.
Crossref
Search ADS
 
2.
Kang
,
S.
,
Johnston
,
J. P.
,
Arima
,
T.
,
Matsunaga
,
M.
,
Tsuru
,
H.
, and
Prinz
,
F. B.
, 2003, “
Micro-Scale Radial-Flow Compressor Impeller Made of Silicon Nitride-Manufacturing and Performance
,”
Proc. ASME Turbo Expo 2003
,
Atlanta, GA
, June 16–19, Paper No. GT2003-38933.
3.
Peirs
,
J.
,
Reynaerts
,
D.
, and
Verplaetsen
,
F.
, 2004, “
A Microturbine for Electric Power Generation
,”
Sens. Actuators, A
0924-4247,
113
, pp.
86
–
93
.
Crossref
Search ADS
 
4.
Tanaka
,
S.
,
Isomura
,
K.
,
Togo
,
S.
, and
Esashi
,
M.
, 2004, “
Turbo Test Rig With Hydroinertia Air Bearings for a Palmtop Gas Turbine
,”
J. Micromech. Microeng.
0960-1317,
16
, pp.
1449
–
1454
.
5.
Isomura
,
K.
,
Tanaka
,
S.
,
Togo
,
S.
,
Kanebako
,
H.
,
Murayama
,
M.
,
Saji
,
N.
,
Sato
,
F.
, and
Esashi
,
M.
, 2004, “
Development of Micromachine Gas Turbine for Portable Power Generation
,”
JSME Int. J., Ser. B
1340-8054,
47
, pp.
459
–
464
.
Crossref
Search ADS
 
6.
Isomura
,
K.
,
Murayama
,
M.
, and
Kawakubo
,
T.
, 2001, “
Feasibility Study of a Gas Turbine at Micro Scale
,”
Proc. ASME Turbo Expo 2001
,
New Orleans, LA
, June 4–7, Paper No. GT-101.
7.
Mori
,
A.
, and
Mori
,
H.
, 1981, “
Modified Reynolds Equations and Boundary Conditions for Analyses of Dynamic Performances of Externally Pressurized Gas Bearings
,”
Proc. 8th International Gas Bearing Symposium
,
Leicester, UK
, Paper No. 16, pp.
217
–
228
.
8.
Salehi
,
M.
,
Heshmat
,
H.
,
Walton
, II
J. F.
, and
Tomaszewski
,
M.
, 2004, “
Operation of a Mesoscopic Gas Turbine Simulator at Speeds in Excess of 700,000rpm on Foil Bearings
,”
Proc. ASME Turbo Expo 2004
,
Vienna, Austria
, June 14–17, Paper No. GT2004-53870.
9.
Isomura
,
K.
,
Tanaka
,
S.
,
Togo
,
S.
, and
Esashi
,
M.
, 2005, “
Development of High Speed Micro-Gas Bearings for 3-Dimensional Micro-Turbo Machines
,”
J. Micromech. Microeng.
0960-1317,
15
, pp.
S222
–
S227
.
Crossref
Search ADS
 
10.
Hikichi
,
K.
,
Goto
,
S.
,
Togo
,
S.
,
Tanaka
,
S.
, and
Isomura
,
K.
, 2005, “
Hydroinertia Gas Bearings for Micro Spinners
,”
J. Micromech. Microeng.
0960-1317,
15
, pp.
S171
–
S178
.
11.
Liu
,
L. X.
, and
Spakovszky
,
Z.
, 2005, “
Effects of Bearing Stiffness Anisotropy on Hydrostatic Micro Gas Journal Bearing Dynamic Behavior
,”
Proc. ASME Turbo Expo 2005
,
Reno, NV
, June 8–11, Paper No. GT2005-68199.
Copyright © 2007
 by American Society of Mechanical Engineers
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