This paper presents a new flexible hub design for the inside-out ceramic turbine (ICT) rotor configuration. This configuration is used in microturbines to integrate ceramic blades in order to increase turbine inlet temperature (TIT), which leads to higher cycle efficiency values. The ICT uses an outer composite rim to load the ceramic blades in compression by converting the centrifugal loads of the blades into hoop stresses in the composite rim. High stresses in the composite rim lead to high radial displacement of the blades. This displacement is compensated by using flexible hub in order to maintain the contact with the blades. However, hub flexibility can lead to rotordynamic problems as heavy hub deformation will induce high stresses in it. Thus, stresses in the hub are induced by both rotordynamics and centrifugation, requiring a multi-objective design process, which has yielded geometries that limited, until now, the blade tip speed to 358 m/s. In this paper, a simplified rotordynamics finite element model of a flexible hub is developed to allow quick design iterations. Using the model, a design space exploration of this hub concept is done while considering centrifugation and rotordynamics. Experimental validation is conducted on a simplified ICT prototype up to 129 krpm, i.e., an equivalent blade tip speed of 390 m/s. Finally, predictions from the experimentally calibrated model show that the tested prototype hub could reach a blade tip speed of 680 m/s.

References

References
1.
McDonald
,
C. F.
, and
Rodgers
,
C.
,
2005
, “
Ceramic Recuperator and Turbine: The Key to Achieving a 40 Percent Efficient Microturbine
,”
ASME
Paper No. GT2005-68644
.
2.
Coty
,
P. J.
,
1983
, “
Compression Structured Ceramic Turbine Rotor Concept
,”
Ceramics for High-Performance Applications III
,
E. M.
Lenoe
,
R. N.
Katz
, and
J. J.
Burke
, eds.,
Springer
, New York, pp.
427
441
.
3.
Kochrad
,
N.
,
Courtois
,
N.
,
Charette
,
M.
,
Picard
,
B.
,
Landry-Blais
,
A.
,
David
,
R.
,
Plante
,
J.-S.
, and
Picard
,
M.
,
2017
, “
System-Level Performance for Microturbines Using an Inside-out Ceramic Turbines
,”
ASME J. Eng. Gas Turbines Power
,
139
(
6
), p.
062702
.
4.
Courtois
,
N.
,
Ebacher
,
F.
,
Dubois
,
P. K.
,
Kochrad
,
N.
,
Landry
,
C.
,
Charette
,
M.
,
Landry-Blais
,
A.
,
Fréchette
,
L.
,
Plante
,
J.-S.
, and
Picard
,
M.
,
2017
, “
Superalloy Cooling System for the Composite Rim of an Inside-out Ceramic Turbine
,”
ASME
Paper No. GT2017-64007
.
5.
Stoffer
,
L. J.
,
1979
, “
Novel Ceramic Turbine Rotor Concept
,” Air Force Aero Population Laboratory, Cincinnati, OH, Technical Report No.
AFAPL-TR-79-2074
.http://www.dtic.mil/dtic/tr/fulltext/u2/a078669.pdf
6.
Kochendoerfer
,
R.
, 2017, “
Compression Loaded Ceramic Turbine Rotor
,”
AGARD Conference Proceedings
, Vol.
276
, pp.
22.1
22.19
.
7.
Landry
,
C.
,
Dubois
,
P. K.
,
Courtois
,
N.
,
Charron
,
F.
,
Picard
,
M.
, and
Plante
,
J.-S.
,
2016
, “
Development of an Inside-out Ceramic Turbine
,”
ASME
Paper No. GT2016-57041
.
8.
Landry
,
C.
,
Dubois
,
P. K.
,
Plante
,
J. S.
,
Charron
,
F.
, and
Picard
,
M.
,
2017
, “
Rotordynamic of a Highly Flexible Hub for Inside-out Ceramic Turbine Application: Finite Element Modeling and Experimental Validation
,”
ASME J. Vib. Acoust.
,
140
(
1
), p.
011013
.
9.
Kim
,
S. J.
,
Hayat
,
K.
,
Nasir
,
S. U.
, and
Ha
,
S. K.
,
2014
, “
Design and Fabrication of Hybrid Composite Hubs for a Multi-Rim Flywheel Energy Storage System
,”
Compos. Struct.
,
107
, pp.
19
29
.
10.
San Andres
,
L.
,
2010
, “
Notes 13. Squeeze Film Dampers: Operation, Models and Technical Issues
,” Texas A&M University Digital Libraries, College Station, TX.
11.
San Andrés
,
L.
,
2012
, “
Damping and Inertia Coefficients for Two Open Ends Squeeze Film Dampers With a Central Groove: Measurements and Predictions
,”
ASME J. Eng. Gas Turbines Power
,
134
(
10
), p.
102506
.
12.
Andres
,
L. S.
,
2014
, “
Force Coefficients for a Large Clearance Open Ends Squeeze Film Damper With a Central Feed Groove: Experiments and Predictions
,”
Tribol. Int.
,
71
, pp.
17
25
.
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